To make up something on this site, I'll start tutorials and guides; and they're usually for Windows PC.
First tutorial/guide for this page is: Making some space for your games, or in short way, performance boost.
First things first: Is your rig (PC Specs) is enough for you to run games you'd like to install? If it is not, then don't force your PC to run it and instead upgrade your setup or buy a new one. But if your rig is enough to run certain games and you feel or see your rig does not perform well, then this is a 'little' help for your baby! :D
Oh gods, if you don't know if you have met the system requirements, you've got to be kidding me.
•Disable animations/theme of your desktop.
This is the first basic step of troubleshooting your gaming performance. You don't need Aero theme whilst gaming, right? Well, if it does not bother you then go ahead disable your desktop's animations/theme:
1. Go to Start button and right click Computer > Properties > Advanced System Settings > On Advanced Tab > Performance then click Settings...
2. On Visual Effects, click Adjust for best performance then click Apply and OK.
Or: You can choose Windows Classic theme on Personalise for a convenient way.
•Clean up your disk (virtually) and de-fragment it.
You don't know if your disk is full of clustered files and junk files because your attention is at your gaming interest, unless if you're 'friends with your PC.' Despite both, you need to regularly utilise your disk to prevent memory hogging and files scattered around like they were caught in an explosion.
All you have to do with CCleaner is Cleaning (Tab) and Registry (Tab). You may also find the startup tool lovely within the application. On Auslogics' Disk Defrag, you can do Quick Defrag (if you want to use your PC immediately) or Analyse and Defrag (recommended).