Windows 8 works with same method as 7, but just looks different/theme is changed.
Start menu is full of boxes, and settings are hard to change.
You can have own desktop like in Win7, but it doesn't have all features.
If you have touchscreen laptop, Win8 would be nice. Otherwise Win7 best. :P
1. Try changing your windows theme to original (grey one).
2. Go to power settings and change it to performance mode/balanced.
3. Download latest drivers & utility for your GPU, set your GPU to stress performance most.
4. Close un-necessary programs/tasks (Shift+Ctrl+Esc) open task manager and click "processes" tab. Close processer you dont need at that moment and performance will raise.
5. Buy latop cooler (Like I did :P), it will blow cool air from bottom of your laptop, CPU cooler will get cooler air = runs better as cool. (Other parts get cooler too)
6. Delete useless programs and setups, setups can be deleted after you installed any program.
If you dont really need any file or program, delete/uninstall it.
7. Delete shortcuts from your desktop, as much as you can. PC will startup and load desktop faster.
8. Download CCleaner
http://www.piriform.com/ccleaner/download/standard
Clear browsers and other locations from junk and useless stuff. (You can also uninstall stuff with CCleaner)
Scan/Fix registrys with CCleaner.
9. Clear your HDD with disk defragmenter
http://www.sendspace.com/file/6pvw7e Scan and fix, it will arrange files and make them open faster.
10. Scan threats with HitmanPro and Malwarebytes (Scan for viruses)
11. Scan PC with AdwCleaner
http://www.bleepingcomputer.com/download/adwcleaner/ (Tap scan, and then delete button)
12. Dont use much tabs same time (Btw use Chrome) and especially any players like youtube.
13. Use low settings, ask for ultra low graphic configs if you are playing ET.
Just minimize usage and increase performance.

Hope it helped, just ask if you got questions.