What genres are you playing? Do you prefer high-quality games or more indie style games? Are you also interested in older games that are still good, or do you need new stuff thats 1-2 years old at most?
Apart from the genre of games you might like, you also need to consider what your PC can handle. Some games are far more demanding of computer resources. Games usually list the basic and/or recommended system requirements needed to play. The major considerations are the level of your processor, graphics card and amount of RAM.
If you're just getting into PC gaming, I would strongly recommend the PCgamingwiki site. It's an amazing resource full of fixes for games, if you have a problem with a game odds are that that site has a fix listed on it.