What you'll need to do the job:
Allen and socket wrenches as supplied in the tool kit. A replacement filter if needed, soapy warm water, air hose, foam filter cleaner, foam filter oil, hair dryer.

Cleaning and/or replacing the air filter should be done with every oil change. Air filters trap the gunk that flies through the air and tries to worm its way into the bike's engine which could cause damage. Air filters require attention at the same time you do your oil change. To change or clean them, the first step is to remove the gas tank. Your owner's manual will tell you exactly where the bolts are to remove the tank and where the filter is located. Remember to turn the gas off before doing this. Next, open the air-box if you have one. The filter should slip right out. Some bikes have their air-boxes in rather inaccessible places. If this is the case with your bike, attention to the filter is necessary when you bring your bike in for a tune-up. If you have cone filters, just unscrew the hold bolt and slip off.

If you have a paper filter, at this point just throw it away and install a new one. If you have a foam filter you can blow it clean with pressured air or clean with soapy warm water, or replace if needed. Or use foam filter cleaner and warm water. Clean until you can hold it up to light and see through it, then air dry or use a hair dryer to dry. Once dry, massage in foam filter oil let it dry and replace. Also at every oil change, check your spark plugs, in addition to the owner's manual recommended schedule. Generally about every 10,000-15,000 miles plugs should be changed. This is generally done at a tune-up, so if you're taking your bike in to a shop at regular intervals, make sure they actually change them. (Ask for the old plugs back.) When checking them, you're looking to see if they are sooty or have deposits. If so, you need a tune-up. You may have a timing problem, carburettor synchronization problem, or the pilot jet plugged. If they are black and fouled, then your engine is burning oil, which could mean a valve problem, or the piston rings are completely shot. In both cases, take your bike into the shop for some engine work.