Team Building Ideas

[TenCodeRiot]

I'm fairly new to competitive building and was wondering if someone can give me the run down on a team that would make sense. I want to know what Pokemon to use mostly instead of actual builds. By that I mean what compliments the ideas I already have. Want to make sure I don't have too much of one thing like too many physicals or specials. I want to get a good coverage going. So far I really want to use Gyarados on my team as he is my favorite and I've heard mega Salamence is just too good to pass up so I guess that would be my one mega. What would go well with those two? Would an Amoongus fit well? What's some ideas for type coverage, etc?