There are several things that might improve a MacBook's performance, but first it would be good to know what is it that you believe is slow? Is there a slow down with Internet access? Do you have problems with one particular application or document? Or is it just everything seems to take forever? Is the issue constant or intermittent? Has it always been this way or has something changed?
Some other questions -
What model MacBook do you have?
How much RAM installed in it?
How much free space do you have on your hard drive, as a percentage of total space?
Let us know, we will keep working with you.
Best of luck.
Yes, laundry bleach is right, there are many ways to speed up your MacBook. For instance, RAM upgrades, SSD etc.
I just wrote an article about upgrading a MacBook, if you are interested: