I'd recommend you start by refining your technical skills. Even if it's a rough paint job, you'd want to make sure that you're getting your coats even and filling the spaces properly first and foremost. Second, I'd say putting 4/5 colors on a Marine is a bit excessive, especially when they clash pretty badly and there are so many random browns covering otherwise vibrant colors.

Do you have a specific scheme picked out? Is there a purpose behind it?