Long list, but most of it's really easy. Just the first is really important to check right away. I tend to check it often, not at every oil change, but any time I'm mucking about with it more than a little.
Open the #1 fuel bowl drain (hose on the nipple, dumping into a gas can - duh!) with the petcock to ON or Run, then Reserve. Make sure the gas stops after a little. If it keeps running, the petcock needs rebuilt or replacement. Making sure the petcock is good, along with the float needle valves, are imperative.
Check the engine mount bolts for 1) they're there and 2) they're tightened to spec and 3) there's no gap between the frame and engine at the spec'd torque. If there is, pull the upper left bolt and shim the gap. Search again
Make sure you at least check the level and condition of all fluids. Brakes, coolant, rear drive, engine and forks. OH, the shock too - ok, it's not intended to be checked or changed but it can be done. Use the search.
Look for leaks while you're doin' the above.
Be on the lookout for missing or deteriorated rubber bits (grommets, spacers, TIRES). Except for tires, they're not very expensive if you get them online (I like Ron Ayers) and if you get several of 'em the shipping isn't killer.
Air filter - check it. Look to make sure the carb boots are seated both in the air box and around the carb inlets. Look at the lower front of the air box to see if it's starting to come apart. I gotta use the Search for that one