Maintenance does depend to a certain extent on the type of fish you keep and the setup of your tank. General principals are as follows though:
Daily
1. Check temperature of tank. Keep an eye out for broken heaters,
filters and other equipment
2. Check general appearance and health of fish. (Any out of character behaviour, not eating, hiding, visible signs of disease on body etc.)
3. Check tank for signs of leakage.
4. Feed fish.
starve day once a week
5. Replant plants if nescessary, remove dead leaves, pest snails etc on sight
Weekly
1. Clean algae from glass with algae scrubber, toothbrush and fingers for awkward bits.
2. Squeeze out filter floss in old tank water.
depends a little what filter media you using, personally i wouldn't clean every week, when i'm doing a water change i check the output of the filter, if it has dropped then the media needs a squeeze out in tank water, too much cleaning can create more problems.
3. Gravel vac substrate. Stop once you've removed about 20% of your water.
30% for me... being pedantic now sorry!
4. Replace with dechlorinated water.
5. Wipe over and polish (optional) outside of tank.
6. Clean your light cover.
Fortnightly
1. Squeeze out filter wool carefully in old tank water. Dont go over the top though. That brown gunk is good.
2. Trim plants with scissors.
Every 3 months
1. Service filter. Completely remove and clean all parts.
just as a reminder, make sure when you service your filter that you leave your filter media in a bucket of tank water to keep the bacteria alive.
2. Clean all pipework. Pins, pipe cleaners and cotton buds are a great help.
Every 6 months
1. Check lighting and replace tubes.