Feet are slightly more than shoulder width apart. Flat soled shoes.
My warm up lasts about 20 minutes. It's mostly dynamic stretching. I have been doing the following with weight (squats): warm up set (not very deep), stretch/depth (very deep), warm up set again (normal depth), weight acclimation (normal depth). And some of the sets I repeat. I never do consecutive sets during my warm up. I do some work with a resistance band also. I do several other things such as bodyweight squats, unilateral bw squats, ankle stretches, etc. I go more by feel than anything...some things are always part of the warmup, while others aren't. So far, the longer I spend warming up, the more easily I get through my sets (weight feels lighter and I'm more fluid). In the mornings or if I've been sitting for the past few hours before going to the gym, I will walk or jog for a few minutes to get loosened up before starting my typical warm up. Overall it's pretty solid. I just need to stick with it. I feel like it's a pretty effective warm up. I think I'm just feeling my age...all 22 years of it