I start out by wiping the front with a rag and some isopropyl alcohol. I clean the rear by pouring some of the alcohol (if you don't have isopropyl alcohol, a quality Scotch works too) into the back of the lens and shaking it sort of like you might a martini for James Bond. If there's any gunk on the front, I've found a piece of 5,000 grit sandpaper cut into a small disk and mounted on a Dremel or other (I recently moved up to using a Foredom unit) rotary tool mandrel gets it off quickly (note: wetting the sandpaper helps for the next step). If I have to use the sandpaper, I then also use a felt wheel on the rotary tool, usually with a flexible shaft attachment (if you're using a Foredom, it already has this, you only need to buy it for other rotary tools) to help remove any scratch marks. I'll usually use some sort of polishing medium as well, but you have to be sure to keep wiping it off if you use any. To finish removing any scratches I used to use a standard dual wheel buffer, that works - - but - - I've since found that mounting a buffing wheel in between centers on my 24" wood lathe is better since I can pop the wheel into the laundry machine each time. After this you want to remove any dust or dirt the process created, so I use a water pressure cleaner. If you don't have one, you can use a power water jet attachment for your garden hose. You have to dry it after this step. I use a heat gun. When you start to smell the electronics burning a little bit, you know you're almost done, so stop the heat gun then and just let it sit. The residual heat will do the rest.
If you follow the above procedure the last step is to chuck your lens into the trash.
Kidding aside, I use a Giottos rocket blower. I don't know what size (does it say somewhere?)? I used to use a Lenspen Original, but I gave it to my father recently because he didn't have anything for his camera. I just ordered the DSLR kit. I'm excited to use the newer ones with the supposedly colorless translucent carbon. I never had any trouble with the black carbon, but I always wondered if the day might come when that changed.