Pull the plug and clean it, pull the air filter and clean or replace it, with the plug out of the cylinder cycle the motor a few times - as if you're trying to start it - but cover anything you don't want gunk to get on. If there's residual oil in the cylinder this can help flush it out.
Of course like the last answers mentioned, your spark plug's gap should be correct, and it would be wise to make sure you have the correct amount of oil in it.
If the air filter is paper, replace it. If it's a foam filter, use some foam filter cleaner, not something as abrasive and destructive as brake/carb cleaner. A mild dish washing soap and hot water in your kitchen sink will do the job but not too hot that the rim of the air filter falls off because the temp disrupted the adhesive.
Spark plugs are fine with being cleaned with the brake/carb cleaner but I'd go with the brake cleaner. I find it evaporates better with less residue.