Here are just a few gardening tips that I've found useful over the years. It has helped my gardens flourish and the plants to grow nicely over the years. Tip # 1 - Weeding
Make sure you keep your gardens well weeded. The easiest way is to keep on top of it by removing the weeds when you see them.
Tip # 2 - Watering
Where I come from, the best time of day to water your gardens is before sunrise. This method reduces the amount of moss and mold that may grow in the garden. Usually, though, this is not possible for everyone as you need either a timer or a timed sprinkler system installed.
If you can't water at the optimal time, then make sure that it is done when the sun is no longer at it's hottest point in the sky. Very late afternoons and early evenings (around what most would consider is dinner time) would suffice.
Tip # 3 - Enough water - how to tell
The 2 methods that I typically use to water my gardens is 1 - with a regular hose. This saturates the surface well and the water soaks into the soil. I would say that about 15 minutes or so on 1 area should suffice. 2 - use soaker hoses whenever possible. These hoses use a drip method to provide water to the gardens. You can turn the water on and walk away for approximately 1 hour or so. This reduces the amount of water that evaporates into the air.
Tip # 4 - Fertilize
Gardens need to be fed as well. Try to stay away from the typical chemical based fertilizers. Miracle grow in the powder version with the hose attachment usually works really well. It helps give the plants lots of nutrients and even though it says weekly, I found that it still works quite well every other week.
Try some of these methods out yourself and see what kind of results you get. Remember, the results will also vary depending on your location.