Making Gaming Song Parodies

So, me and my friends are interested in doing song gaming parodies, and theres a couple of things id like to know:
1:How do i not get copyrighted? I know that theres something with changing the instrumental, but i dont know if its enough.
2:Since i sound like a cat going through a coffee maker, i would like to know how to use autotune(if you could link some tuts that would be great)
3:Is there something else i need to know?

1. Usually unless you copy a song from a game you should be fine, yes changing instruments or just by editing the song and adding IDK a clap sound is enough.

2. I think google is your best friend.

3. You should check out Smosh on YouTube, they've got some cool song gaming parodies, and other YouTubers,

1) The law has changed since 2012, so you don't need to worry about that.

2) Great tutorials on Youtube that can help with that.

3) Go for it.

Thanks alot to everyone who posted, and helped me, and now i think i want to know how to change the instrumental? I know i should use google, but at least tell me where to get started.

@PredatorRules: All of the tutorials i find are REALLY complicated, something like picth correct or something else, i dont need those i need to know how to use autotune for a person who cant sing. If you could link some, that would be great.

Try this: https://www.youtube.com/watch?v=mpEPFc_1ibA