Guitar Hero: Aerosmith

This one is fun and easy. Eventually you can have the option to unlock and purchase both characters. Get in a cop-op match with a buddy, either online or off, and pick the two characters. One must be Tom, and the other Brad. Now, finish a song, and the cheevo pops.

I've got another way to do this on your own. Go select "Joe Perry Guitar Battle", and since the solos alternate between players, you can actually play this on both guitars by pausing and switching guitars when you see notes coming for the other part (usually you would want to pause and switch when a starpower phrase is coming up for the other guitar). To activate, just unpause quick, press both select buttons, repause and get situated for whichever is playing next. It takes a little while, but I actually was in the green for most of the song!

But seriously, if at all possible, just find someone to do a quick song with you online or off. Much easier than what I had to resort to. :D

If you absolutely can't get anyone else to play with you (not surprising considering how dead online is), it is actually possible to do this by yourself. You'll want to play Walk This Way (Run D.M.C.) on Easy. This song has very few bass notes. Put a rubber band on the second guitar's green fret to hold it down. You're going to have to play the bass part with your feet. Try to hit the yellow notes in the verses with your left foot while strumming with your right, because most of the time there are two yellows to every one green, and ignore the greens and reds. When the chorus comes up, try your best to hit every note (there are no yellows, so you only need to fret red with your left foot when it comes up). If you can't, at least hit 3 out of every 4. You'll later get to a part with no yellows, only a lot of greens and a red every so often. Continue ignoring all the red notes, and only hit green. The bass should be over before the final solo.

This is pretty ridiculous, lol, so I'd only suggest it if you have no way of getting another person. I couldn't find anyone online and my only friend who can play this game wasn't available and I am damn impatient. Also, if you ever need to activate star power, pause, tilt both guitars up, and unpause then repause quickly and get back into playing position.