Often when learning a new exercise a good cue, choice of words or something to focus on can be the "eureka!" moment that you need in order to grasp the desired technique. The point when you "get it!"
Every person is different, some are visual learners, some like to listen to coaching cues and tweaks while others need to be physically put in the correct position first time round; most benefit from a combination of all three.
However, these are 10 things to focus on / cues / top tips when practicing lifts or, ideally, if you're new to specific exercises. It's much easier to learn something than it is to re-learn something.
1 - Push Yourself into the Bench: After you have lowered the bar to your chest, instead of focusing on pushing the bar away from you, imagine that you are trying to push yourself into the bench and drive away from the bar. As you press yourself into the bench you will engage your lats and also make yourself wider. This gives you a much wider and more stable base to press from while allowing to push with maximal effort.
2 - Deadlift in Socks: Deadlifting in socks has multiple benefits. 1) You're instantly lower to the ground and so you don't need to lift as far (sounds petty but it makes a big difference). 2) It allows you to keep your weight predominantly on your heels and engage your hamstring better while not tipping forwards too far ahead of the bar. 3) It give you 100% recoil from the floor; no power is leaked and dispersed through the cushioning in your shoes. 4) The proprioception in your feet is improved and you are now much more grounded, balanced and stable.
3 - Take the Tension Out of the Bar: Just before starting your deadlift, squeeze your shoulder blades back and take the strain of the bar a little. If you're lifting and you can hear the bar clinking into place as it fills the hole in the plate then you're doing it wrong; it should be a silent lift without plates clinking during the initial pull. This will avoid you having a second pull as you hit resistance. By doing this brace/squeeze of the shoulder blades you will help to keep your spine in place throughout the lift. If you're not quite sure what I mean, check out this quick video: http://www.youtube.com/watch?v=iboVuB-Ig3k
4 - Screw Your Feet into the Floor: Before squatting, imagine your feet are on two plates. Without moving the position of your toes, screw your feet into the floor (right one clockwise, left anti-clockwise) to create some tension and stability in your hips and improve the knee alignment. Try to keep this tension as you sit into the squat position and it will improve your posture, stability and knee alignment throughout the exercise.
5 - Move Your Hips First, NOT your Knees: A common mistake, particularly among women (that's not sexist - it's factual) when squatting is that the knees ride forwards towards the toes. This is an ineffective movement pattern that will add unnecessary strain to your back and knees and not allow you to lift as heavy or as safely. Most people assume that the first movement for a squat is to bend at the knees.;in fact, in order to engage the hamstrings and glutes correctly and maintain a strong position it's important to tuck your hips and move your hips backwards first. This will keep the weight on your heels and avoid the knees from riding forwards.
This guy talks you through it: http://www.youtube.com/watch?v=dbxxs1PErLQ
6 - Break the Bar: Being a lower body exercise, many people under estimate the importance of the upper body when squatting. Make sure that you don't relax your hands and rest them on the bar. instead, grip the bar tightly and try to "break the bar" over your shoulders as you squat. Brace/Pull down the most at the bottom of the squat. This will add the required tension in the upper back to keep you more upright and squat with the desired posture.
7 - Hinge Don't Squat: A kettlbell swing is a hinge movement, NOT a squat. If you want to swing with more power then hinge more, don't squat lower. The kettlebell should never swing near to your knees, it should only just clear your groin no matter what weight or range you swing with.
8 - Keep the Arm in Contact with the Body for as Long as Possible: During the back swing and the swing try to keep your upper arm and body in contact with one another for as long as possible. It's not an upper body lift so the effort should come from the hip thrust rather than any upper body strength. On the way down you shouldn't sit back and wait for the kettlebell to come down (ESPECIALLY as you swing heavier). This limits your potential power output. Instead, wait for the kettlebell to fall and pass under with you as your arm re-makes contact with the body. Watch this video if you're unsure: http://www.youtube.com/watch?v=0_XjJjLc7NE
9 - Push Your Chest Towards the Bar: During all "pull" exercises (pull ups, bent over row, seated row etc) it's important to avoid internal rotation of the shoulder. Instead, exaggerate a good posture by bracing in the lower back and maintaining a natural arch in the lower spine, pushing your chest towards whatever object you're moving as you pull. This is probably easiest with a bent over row or seated pull - try to hit your upper ribs on the bar or handle as you pull.
10 - Warm Up Specifically and Mobilise Specific Joints and Groups of Muscles: I over-looked the benefits of a specific warm up for a long time. A decent warm up (where you ACTUALLY feel warm) should leave you feeling warm, mobilised and mentally ready for the workout ahead. not only will this help with avoiding injuries but it's also crucial to offer you the mental preparedness for maximal effort. Consistently warming up well and mobilising post workout will also help to improve mobility issues and can improve rehabilitation time from injuries and minimise discomfort from existing injuries or muscular soreness - don't keep skipping this!