YOu've gotten some good advice. Anywhere from 10%-30% weekly water changes are good. Gravel vac at least once a month, but every water change or every other water change would be better. Since this is a new tank, and it is cycling, you may need to do more frequent water changes in the beginning. If your fish are looking stressed or acting odd, I'd do a water change and go from there. (if you've got test kits, you could test for ammonia or nitrites, which will spike at some point in the cycle, if they spike too high, you would need to change the water). What plants did you get? Most plants need 8-12+ hours of light a day.
As for feeding, it is true that overfeeding is much worse than underfeeding, and while your tank is new, feeding lightly may be better. However, every other day is not really an ideal regimen in the long run. I prefer a couple of smaller meals a day rather than one large one. Often, with one large meal, food goes uneaten and rots at the bottom. With two smaller meals, the food is all eaten. Though, it will turn to fish waste, which will also rot at the bottom... Fish will always act hungry and can be very good at begging for food, so don't give in to the temptation to feed them all the time... I also wouldn't go with the "5 flakes" thing. Put a very small pinch (ground up) in the tank. Watch the fish eat. If they eat it all in 1min. Add a bit more. If it's been 3-5 min, and food is falling to the bottom, feed less next time. If lots of food falls to the bottom, do a gravel vac with each water change. Once the tank has cycled, you could add some bottom feeders to clean up the food that falls to the bottom. (but then you'd still need to vacuum up the fish waste).
As for letting the water sit, it all depends on your water. You want to use a good dechlorinator that removes both chlorine and chloramine. Usually, there is no need to let the water sit after that. However, some water has a lot of disolved CO2 in it to keep the PH around 7. As the CO2 gasses out, the PH of the water rises. If this is the case, then it's best to let the water sit out a while. To find out if this is the case, test the pH of the water from your tap. Then, let the water sit out for about 24-48 hrs. Test the PH again. If it is much higher, you will want to let it sit before using it. IF its' the same (or nearly so) you are fine to use it with just the dechlor and not letting it sit.
Emily