If you're thinking of mining Bitcoin with your GPU, you're out of luck. It's been impossible to profit off Bitcoin mining without an ASIC for a while now. You may be able to make a money out of mining alts though.
I see you mentioned Ethereum specifically, so to know whether you can mine it profitably:
1) Find out the hashrate of your GPU using a site like
this.
2) Use a mining calculator like
this and fill it in with your GPU hashrate and other required info.
I don't mine Eth so I can't vouch for the accuracy of these sites, but that's the general idea. You should be able to find similar tools for other alts.