Start with the steeping times listed below as general guidelines, but more importantly, try it for yourself and see what you prefer. If it isn't suiting your buds, try varying the water to tea ratio, the brewing temperature and/or the brewing time.
If your tea tastes bitter or harsh to you, reduce the brewing time (and possibly also the temperature). If you prefer your tea strong, add more tea leaves to your brew instead of adding time which will only risk making a bitter cup.
If your tea lacks nuance and complexity, it may be an issue of the brewing time being too short or long, but it's more likely an issue of brew temperature or water to leaf ratio (not enough leaves for the amount of water you're using).
Black I 1-2 tsp I 200° I 2-3 min
Green I 1-2 tsp I 175° I 2 min
Herbal I 1.5 tsp I 208° I 5-6 min
Maté I 1.5 tsp I 208° I 5-6 min
Oolong I 1-2 tsp I 195° I 3 min
Rooibos I 1.5 tsp I 208° I 5-6 min
White I 1.5 tsp I 175° I 4-5 min