Looks very good, especially for some of the first! I have a few suggestions on what you can do to achieve a better result. Firstly, are you using primer? It’s not necessary but it gives a better look to the paint and helps it cling to your mini. I’m seeing some grayish spots on the marines so my second thought is you may need to double check on how you thin your paint as you may be overdoing it. Lastly I recommend looking at some cheap airbrush setups as it really helps achieve a consistent paintjob and some neat effects.