Now that gas is such an important issue I found out that I can save a nice amount of it just doing the following (no rocket science here) and most of it free.
First, WATCH THE AIR PRESSURE IN YOUR TIRES!!!. This is probably the easiest to check and will give the most return for the 50 cents you will spend at the gas station. Lazyness costs here. A lot. First the added rolling resistance (more gas) and extra wear to the tires (more money). Read the car manual or find a sticker either at the door jamb or inside the trunk. Also check the tire sidewall, look for something like “xx PSI”. Check once a month. And don’t ‘leave for tomorrow’. By the way, in order to get an accurate air pressure reading, tires must be cold (driven one mile or less). The reason is that air expands with temperature rises, so you may have a tire that looks full and is underpressured or you may put too much air in it (overinflated).
Second, you are not driving a race car. Be gentle on the gas pedal (save gas) and you will be gentler also on the brake (save brake pads = save money). Usually I drive along with the pack, not faster or slower (also makes it harder to pick on you, if you know what I mean). When start driving from a stop do not try to beat everybody else, there are no prizes waiting for you or anybody else. And when approaching a yellow or red light or a stop usually I let the car coast from half a block away (or more). If I time it right I may have enough time for a red light to change to green without stopping. Hot rodders will blast along, come to a screeching halt and start again. Not very savvy.
Third, take a look at the maintenance schedule in your car manual and try to stick with it. Clogged air filters (probably you can change them), bad plugs (ditto), bad ignition wires and skipped oil changes add up really fast to operating expenses. With computers taking care of gas mixures now you may not realize, under normal driving conditions, that something is not up to specs. Your friendly mechanics analyzer will tell a lot more. And the longer you wait the more expen$ive it will be.