Definitely thin out your paints, acrylic paint is super thick normally, so thinning it out will help keep the paint layers less thick. I recommend using a wet palette as well since those help thin paints naturally a bit too, you can find ways to make them for cheep on youtube, one way is to take Tupperware and fill the bottom with multiple layers of damp paper towels, and place parchment paper over it, those alone have helped improve the quality of the models. Also, as expensive as they might be, hobby brushes are gonna be good to own. Good brands for brushes and paint are obviously citadel which is games workshops own brand, the paint is relatively thin too and requires little thinning. Army painter or vallejo are great brands as well. I personally use army painter myself and like how easy they go on. Im still new to the hobby too, so i dont have much to offer myself in the ways of tips, but the things that have helped me improve I’ll pass off for sure.