super gotenks,
there are 2 types of lag, one is caused by your computer
the other one is caused by your internet connection
if you are talking about internet lag. you should consider getting an better one
if you are talking about computer lag, you should study your pc to find out what part of it is lacking in calculation power.
but as stated before, we cant help you unless you give us some more info.
about:
what kind of internet connection do you have
what kind of graphical card do you have
what kind of processor do you have
what kind of memory do you have.
these are pretty much the basics of having a computer that can deal with lag