Here is my take.
For a first model it is really good, better then my first attempt.
Looks like some fitting issues. Try putting the pieces togeather befor gluing and don't be afarid to trim areas creating a gap. You can use gell type glue (i use model master liquid cement, it has a metal needel type type making it easy to apply glue) to fill in the gaps. You don't have to sand everything, you can use a hobby knife to to remove excess dry glue or plastic. Liquid glue (it's thinner then water) is good for tight fittings, just apply it where it's out of sight and it'll be sucked into the joint.
Don't worry about colors being off, if you think it's good then it is. Go at your own pace, try one new thing at a time and you'll have fun and learn along the way. Rember this is about fun, not perfection.
You got a nice job done on the weathering, but it is a bit off. Look at a few photos (PrimePortal.net is a good source of reference photos) and compair the mud and weathering to what you have, and adjust how much you put where.
And rember that there is no limit to layers of paint. When hand brushing i usually put on 3 layers, i prefer enemal but it takes 24 hours to dry and you need lots of fresh air because of the harmfull fumes, i haven't had good luck with acrylic paint but there are ways to to hand paint with it and it has very little fumes (still need fresh air).
Mongol General: Conan, What is best in life?
Conan: To crush your enemies, see them driven befor you, and hear the lamentations of the woman!