Can I make my Minecraft run faster?

It played well for awhile. My friend says to just delete the.minecraft and redownload it, but is there another way to make it as fast as it was before?

Turn the clouds off, put the graphics on fast and particles on minimal. Do not bother redownloading minecraft, it will not make any difference.

Everyone think that Turning everything to low helps, no. It. Doesn't! Just Go like this!

Render Distance - Tiny/Short
Particles - Decreased
Soft Light - Maximum
OpenGL - Off
Aniestropic - Off
Clouds - Off

Mine is like that. I have a average computer, and i get 30 - 40 fps

-Use optifine.
-Lower render distance
-Particles down
-opengl off
-gamebooster (maybe if you have limited ram)
-uninstall useless stuff
-check for viruses
-defrag your comp
-upgrade system
-install new drivers that are released
- some others i forgot