This tip is more geared to the commuter cyclist, but is something we all should do.
Get an air pump and a bottle of lube (not WD-40!!). In downtown San Francisco we have many bike commuters and I see tires low on air and squeaky drive trains everyday! Simple and cheap maintenance like this will go a long way.
Wash your bike regularly (once a week). You will notice wear on your chain, cassette and chain rings before they become a big problem. You will be able to notice stress on the frame. You will make your cables/housing, chain, cassette and bar tape last longer.
I don't have a kickstand on any of my bikes. They add weight and look like crap.
However, a bike leant against a post is prone to being knocked by passer-bys and can fall over. You don't want that.
A simple solution I employ is to attach a clothes peg to a convenient cable near the bars (brake or gear). Then when the bike is leant against a post out side the cafe, jam the peg into the front brake lever to lock it on. This makes it much more difficult to knock the bike over.
I prefer a carbon fibre peg (that would be one made of wood).
I use rubbing alcohol to clean my bike, gets grease off really easy, cleans my white bar tape nicely, and best of all it evaporates to nothing, no water left over. also at least twice a year just run through all your bolts and make sure nothing is loose.