Inhale with your lats.

Raise your hands above your head as high as you can, then pull your shoulder blades down sharply and lock them in place. Breathe in through your nose until your belly is full. With your arms still straight, use the muscles in your back to pull them down in front of you, taking a forceful mouth breath down into your sides and back as you do. Flex your abs, obliques and lower back to force this air down and out - making your core rigid all around.
Pull your shoulders down
OVERHEAD INHALE
OVERHEAD INHALE
INHALE WITH YOUR LATS
INHALE WITH YOUR LATS
ARMS UP THEN DOWN
ARMS UP THEN DOWN
Juggernaut
The shoulders should be pulled back and held down at lockout. This ensures optimal stability of the shoulder girdle.
By engaging your lats, depressing your scapulae, and extending your shoulders a bit, you’re repositioning your body’s mass forward slightly, allowing the bar to shift backward a bit at the start of the pull, positioning the center of masses for both the bar and your body closer to the system’s center of gravity.
Stronger By Science
The anti-shrug...consists of moving your shoulders in a downward motion as far as they will go. Once you have moved them as far as they will go, move them a little farther. This tends to tighten not only the shoulders but also the pecs, the back, and the core.
I'm trying to ensure my scapula is locked in, my lats are engaging/depressing, my arms are as long as possible. So when I start I don't get any power leaks... What you want to ensure is [your back] doesn't change position as you're pulling. I get up on the bar and I think 'big broad chest' as I'm setting my brace and everything, but I take my shoulders and I put them back and down... you want to think about your arm length too. I really want that shoulder to be as low as possible because... if we start a little too hiked up and retracted, that arm is going to leak out. So you want to think length: shoulders back and down, chest broad...
Brendan Tietz
Repositioning the scapulae and engaging the lats actually work to decrease the required hip and spinal extension demands of the lift...By engaging the lats more, you can extend the shoulder a bit, letting your shoulders move slightly forward relative to the bar. This also lets your hips move slightly forward, decreasing the hip extension moment arm. Depressing the scapulae serves the same basic purpose: It doesn’t extend the shoulder, but it positions the shoulder joint itself a shade further down your torso, bringing it closer to the hips.
Stronger By Science
I'm trying to ensure my scapula is locked in, my lats are engaging/depressing, my arms are as long as possible. So when I start I don't get any power leaks... What you want to ensure is [your back] doesn't change position as you're pulling. I get up on the bar and I think 'big broad chest' as I'm setting my brace and everything, but I take my shoulders and I put them back and down... you want to think about your arm length too. I really want that shoulder to be as low as possible because... if we start a little too hiked up and retracted, that arm is going to leak out. So you want to think length: shoulders back and down, chest broad...
Brendan Tietz
By engaging your lats, depressing your scapulae, and extending your shoulders a bit, you’re repositioning your body’s mass forward slightly, allowing the bar to shift backward a bit at the start of the pull, positioning the center of masses for both the bar and your body closer to the system’s center of gravity.
Stronger By Science
The shoulders should be pulled back and held down at lockout. This ensures optimal stability of the shoulder girdle.
Repositioning the scapulae and engaging the lats actually work to decrease the required hip and spinal extension demands of the lift...By engaging the lats more, you can extend the shoulder a bit, letting your shoulders move slightly forward relative to the bar. This also lets your hips move slightly forward, decreasing the hip extension moment arm. Depressing the scapulae serves the same basic purpose: It doesn’t extend the shoulder, but it positions the shoulder joint itself a shade further down your torso, bringing it closer to the hips.
Stronger By Science
The anti-shrug...consists of moving your shoulders in a downward motion as far as they will go. Once you have moved them as far as they will go, move them a little farther. This tends to tighten not only the shoulders but also the pecs, the back, and the core.
Breathe in + Flex
I would rather have a full cylinder of air in my torso than one that is already dented...We fill up our stomachs as much as possible with air, trying to look fat like Santa Claus, because that is how we can support the most weight... I would tell you not to pull your stomach in like you're doing a vacuum when you're lifting anything. I would tell you that you will always get more output, more energy, and more strength out if you have a full belly of air and you brace it down like you're about to get kicked by a zebra. (And zebras kick hard.)
Neversate
Pull as much air into your belly as possible, then when you think you have all you can get, pull more.
We're going to take a deep breath in, press our tongue against the roof of our mouth (called the valsalva maneuver) and drive our core out as hard as we can. That's going to stabilize the back. This is what stabilizes your spine. This is what protects your lower back; it's your core.
Super Training
Breathing at the top generally allows for more air to be taken in because there's more space. The abdomen cavity has more room to fill up with more air when you're standing upright rather than when you get bent over and things get kind of compacted and constricted. So that would be the ideal thing: to take your air in all the top, reach down, get set and go.
Juggernaut
Hold that deep, diaphragmatic breath throughout the lift, performing the valsalva maneuver. If you need to exhale and get a fresh breath, do it at the top of the lift or with the bar resting on the ground between reps.
Stronger By Science
I take my breath at the top. I'll take my breath down into the core - really squeezing out against my belt and my abdominal wall - not breathing into the chest. Remember, it's always down here for my neutral spine. I find that builds a lot of pressure... pushing out against my belt. It's going to make it harder for me to find position at the bottom. So I have to manipulate myself even harder, pull myself into the bar even more, and that's going to enable me to lift more weight.
Omar Isuf
When you set your air as you take it in from the top, a very effective tool is to have a quick forceful exhale (setting your rib position down) and then from here, filling up, bracing as hard as possible, and maintaining that more neutral position as you reach down to grab the bar.
Juggernaut
Pull arms down with back muscles
NEUTRAL SPINE
NEUTRAL SPINE
When you pick your hands up, you're stretching your lats... So you stretch them out, and then when you pull them down, you just think about trying to get the opposite motion. You don't have to pull them crazy way back, and you don't have to think about doing anything with them. You don't have to flex them or spread them or anything. You're just trying to pull them down and back as if... you are trying to pull your lats all the way down into your back pockets... Get those lats engaged.
Mind Pump
To properly engage the lats, begin by raising your arms as far above your head as possible as if you were stretching. Try to feel your lats extend, pushing your hands closer to the ceiling. While keeping your lats in that tight position, drop your arms so that your hands are pointing directly at the ground. Keep your arms straight the entire time. Your lats should feel like you’re doing a pullover...Pulling your arms down like this will also engage your traps. Be sure not to shrug your traps at the top of the lift — that’s not helping your lockout and may lead to red lights if the bar descends after the top of your shrug.
You need to engage your lats... as a stabilizing muscle in the deadlift. Your lats are gonna help you to keep your lower back in a flat position. They're gonna help you keep that neutral spine. If you're not engaging the lats, you're gonna have a tendency to round... [and] you're gonna lose a lot of power. In addition, it's placing a lot of stress on your lower back.
Mind Pump
So one way I like to cue that is to do a little reach (up) and exhale before we get down to the bar.
T-Nation
The other thing I like to have people do is to do some very light sets of either pull downs where you're trying to pull down all the way to your belly button... or stiff-arm pull downs like at a tricep machine. You've got your arms out in front of you and you're pulling down... because that's a very similar motion to how you should be getting set.
Juggernaut
When I set up for a deadlift, I raise my hands up because that gives me a nice stretch in my lats and helps me think about my lats. When I pull them down, I'm still thinking about my lats, even though the position is the complete opposite. So that when I get set up, I'm still thinking about my lats. I can still keep them locked in...
Juggernaut
Your lats should be engaged in a good position... if your lats were not engaged in the setup, you're going to have a really tough time making up that real estate. You're going to have a hard time locking out the bar with heavy weights. It's really tough to get your shoulders back if you gave them up earlier in the lift.
Neversate