STEP 1.
Eliminate needless programs. Your Internet connection requires memory to be able to be at the speed you are paying for. If your computer is bogged down by programs you don't need, your connection will be slower. Close programs you aren't using.
STEP 2.
Do a virus and spyware scan. Viruses and spyware also use up memory which can contribute to a connection appearing slow. Run a thorough or complete scan of each even if you have it on and scanning. A regular scan will catch additional items.
STEP 3.
Make sure you aren’t running two firewalls. These will interfere with each other and, in addition to posing security problems, also reduce your web performance. In particular, if you use Windows but have downloaded or purchased a separate firewall, double-check that you aren’t also running Windows Firewall (which is turned on as a default). Go to Search > Windows Firewall and, if necessary, hit Change Settings to turn it off.
STEP 4.
Check your free space. If your hard drive is nearly full, take files you don't use often and either burn them to CD or DVD, place on an external hard drive, or delete them. Your computer uses free hard drive space as virtual memory, so a full hard drive will slow down your computer and your connection.
STEP 5.
Run a disk defragmentation. This should be done once every two weeks. It will improve your overall performance which can only help your Internet connection.
STEP 6.
Consider a computer upgrade. An older computer may not have the power to make use of many things on the Internet now. Even something as simple as a RAM (Random Access Memory) upgrade could help, but if your computer is more than five years old, it may be time to consider getting a newer model OR using a different operating system. Rolling back to an older windows version such as windows XP or trying out various Linux distributions, this often breaths life into an old computer. You can even get an OS that can boot directly to a browser if its the main thing you use it for (xPud, browserLinux, slitaz etc)!
STEP 7.
Turn off your computer every night. Leaving your computer in standby mode without turning it on and off completely every day or so will tie up memory and can soon slow down your Internet speed.