I've attacked GameMaker on and off for a few years, now. I'm still terrible at the programming aspect of it, but I can do enough to make most things function. Buggy as hell, but function. Barely.
I decided to have another swing at making a game again (You say simple, I think platformer) and an idea struck me. Here I am, making graphics without any programming. What are the chances that a programmer has made an engine without any graphics? A few quick minutes in google, and sure enough, there are a couple decent, pre-programmed platformer engines built for and on GameMaker. Most of the people that have made these simply ask that you stick their name in the credits. I, for one, don't actually plan to finish the game, but simply to have a fair exuse to attempt to put some things together.
These engines go into fair detail. The one I have is essentially a super mario clone. You can go up and down slopes without skipping, you can run and "fly" like in mario, jump on enemies' heads, stand on a moving platform, get pushed by a moving platform, disrupt the path of a moving platform etc etc etc. The code has notes in it "// do not edit this" or "// change these variables to make the character jump higher" and isn't that hard to get working correctly. Find an engine that has the basics of what you want to accomplish, and make a simple platformer, if you want.
I myself have tried working with a couple ambitious people (volunteer) on their game projects. Even though the vast majority of these aren't completed (I've one half-success out of a good 10 attempts) they do provide you with further experience. Keep trying, and remember that one small success is much better than a huge failure.