Advice to improve gesture drawings

Hey everyone, first post here, a little nervous but I knew it was time to get some critique!

Recently I’ve been trying to improve my gesture/figure drawings, and I aim to draw from reference for 30 minutes several times a week. But for a while I've felt like I'm stuck in a plateau and I'm not really sure what to do to improve. I feel like my sketches are lacking something but I can't exactly pinpoint what it is. I’m open to any advice or critique :)

Here's some of my 5 minute gestures (with a few 30s-1m ones thrown in there as well) 
https://imgur.com/a/vjlCxDG