Honestly, im sick of everybody saying "thin your paints to milk like consistency". Though it works, not a lot of people understand this thickness it seems. For another way to think about it, thin them until they run off of your brush like ink from a good, liquid ink pen. Im sure you have one of those Uniball pens or similar laying around; this is what I mean. (Sorry if I sounded like a d*ck here. Didnt mean to! Haha)
Other than that, keep your paints wet with a wet pallet. Youtube and the dollarstore are your friend here, toooons of videos and it costs maybe 5$ to make with household stuff.
Thin, thin, thin. Its better to paint in multiple thin layers (especially whites, reds and yellows!) than 1-2 layers of thick paint

. I should also point out that most paints are translucent and allow pigment from underneath to show. Light over dark is still rather dark and visa versa.
Be patient! Let your layers dry before you paint on the next layer. The thinner the paint, the more time it needs to dry. If you paint on a semi dry layer, it rubs, lifts, clumps and does all kinds of nasty stuff that is easy to avoid by just being patient. To help with this, paint a few models at a time. Inusually do 2-3. Oh!, leave ample time for glazes and washes. I let those stand for anywhere from 30 mins to over night.
Use every angle of your brush. The sides of your brush work well for edge hilights, the tip of your brush can be manipulated for different tasks. Point it by rolling it on your tongue, the back of your hand, paper towel etc., for detail work. Flatten it along your tongue, paper towel etc., for a wider brush to cover more area.
Most importantly, be patient with yourself and understand its a process. Just keep practicing and plugging away. Dont forget to keep your brushes clean and in good shape. Take care of your tools and your tools will take care of you!
AND DONT BE AFRAID
TO POST PICTURES. This allows others to C&C your work. Remember, you can always ignore advice, but you should always take it
Hoefully this helps

!