These are some examples of common mistakes people make when using a suspension trainer.
The main issues are they are too loose and just kinda flop backwards; they don't engage the core, so sag in the middle; and they aren't controlling the movement i.e they are just mindlessly getting through the workout so they can go do something else.
Technique is never set in stone and even our tip not to put your knees past your toes when squatting only really applies in most, but not all, situations. For example, if you intentionally train to put your knees past your toes then it's a valid movement and lots of dancers and yogis do it all the time, but for most people, especially those newer to exercise, try to focus on sitting back and keeping your knees above your toes. The great thing about a suspension trainer is it makes doing this very easy as you're essentially holding on to something as you sit back.
Here are some general tips to improve exercise form.
Be intentional: People often seem distracted when performing an exercise. On one level, this is fine as moving is usually better than not moving but if you want to progress you need to work on getting better. This means being intentional with your movements, like a dancer. It can help to imagine you are standing in front of a classroom of school children and you're demonstrating how it should be done. Simply thinking this way will help you focus on doing it as well as you can.
Mind body connection: This is an important part of any kind of movement training. Again like above, you're training to improve, not doing a chore. Try closing your eyes (or not) and placing your attention on a body part, like your butt, and feeling how it moves. Among other things this will help you integrate all your individual body parts into a cohesive whole.
Film yourself: Easy to do with a smart phone. Watch it and see what you look like. Any areas you could improve? Send it to firstname.lastname@example.org and he will happily give you some feedback.
Hire a personal trainer: If you're new this is especially useful but a good trainer can help anyone from grandpa Joe exercising for the first time since high school to Tom Brady trying to keep his body going for one more season, so hiring a PT is something to consider.