Is your bike dirty? Clean it. Make a pile of things on your floor:

>frame, fork
>bars, stem
>seat post, saddle
>wheels, skewers, axles, tires
>brake calipers, derailleurs
>shifters, brake levers
>cables, housings
>chainrings, cassette
>crank arms, pedals
>all bearings, headset, etc
>all bolts, clamps, barrel adjusters

Wash everything with warm soapy water (in order of cleanest to dirtiest) and dry with a towel. Ensure ALL grit is removed from everything. Inspect the frame for corrosion and spray a light mist of rust inhibitor inside it if it's steel or aluminum (aluminum still oxidizes). Make sure your rim tape is in good shape and free from burrs, and that all spokes are tensioned and that wheels are true. Check your brake pads. Make sure your derailleur jockeys aren't worn down or sitting loosely on their bearings. Ensure there is no grit inside your derailleurs and wash and oil the b-knuckle and springs. Check your chainrings and cassette for wear. Check your chain for stretch (simplest way is to compare its length to a new chain). Inspect all cables and housings for wear especially at any bends. Take a tiny wad of toilet paper and soak it in oil. Using your cables, push it through the housings to remove metal / plastic residue that can cause wear and sticky operation. Apply oil to your cables before re-routing them. Clean all threaded items, and apply anti-seize to the threads on your pedals. Ensure your bearings all spin effortlessly and have no pitting, then re-pack them with grease. If any make grinding noises after being re-packed, they will need to be replaced. Once you have it reassembled, lightly oil all mechanical parts.

If you only have one bike, get a second one with similar components. It will make a full annual inspection / overhaul more feasible, therefore you will be more likely to do it. You can spread out maintenance costs and perhaps even have fun. Take care of your bike! Maintenance is relaxing and fun if you don't have to rush it.