This tutorial really opened up my world when it came to painting figures; https://www.youtube.com/watch?v=i-rsH9wdaVg
I use this same technique on clothing with great results as well. You just have to practice and not give up.
Start with blocking first - Getting good clean lines between your colors. So that a shirt sleeve and hand are separate and the colors don't bleed over each other. Clean blocking will get you good results to start from, then you can build apon the basic paint scheme with layers of thinner paint from that point and work your way up from there.
It will take some time before you get the hang of it, but it does start to get better as long as you stick with it.
Just don't give up on yourself.
There is a lot more information available in the figure painting section and if you have questions, we most likely have the answers.
I hope to see some examples of your work eventually. We can guide you better once we can see where your skills are at currently.
Hope this helps! :D