I am about to start working on a game for android devices, in my spare time, to get familiar with android development. I'm more interested in using the best practices possible than getting a quick result, and that is why I need some guidance regarding graphics.

I think the game is going to be fully sprite based. Everything is going to be in .bmp form, or something similar, and my question is:

Should I design the sprites in a small resolution (ie for phone screens) and scale them up to fit into larger screens (tablet screens), should I do it vice-versa or should I consider a completely different approach? Would designing a different set of sprites for each of the most used resolution settings be worth it or are there simpler solutions to the problem with fewer drawbacks than the ones I mentioned above? (If I follow the first approach, for example, the larger the screen the worse the graphics will get, since every pixel of the original drawing will cover several pixels on the screen). Is there a standard approach for dealing with this kind of problems?

If you need me to be more detailed or more clear about something I mentioned (or forgot to) please don't hesitate to ask. Also, excuse me for any inaccurate use of the English language.

Thank you in advance for your input.