I could spend paragraphs talking about staging and height and props; in fact, i have so here is the link to that post.
The most important thing to know, in fact probably the only thing you really need to know, is that the answer is light.
Light is everything.
Finding the right location with the right light at the right time of day is hard, but once you do everything else is a cinch.
My first shoot for Etsy took hours and hours and days. Some things i shot at 3 or 4 different times. It seemed like it took forever to find the right combination, but now that i have, the actual photography takes almost no time at all.
Now all i have to do is wait for the correct conditions. If light is the number one answer, patience is number two. Be ready to wait. These three pictures were taken 4 minutes apart:
|too much sun|
|ahhhhh... just right|
Be sure as you are taking all those pics that you are changing your angles, perspective and distance. You don't want 30 pics of the same thing, but rather full shots, close-ups, up shots, down shots and even some crazy shots.
As for the question of shooting indoors and using non-natural light, well... good luck to you. I did a bunch of my card pictures indoors and the lighting was too frustrating. I would rather wait for a sunny day then play with white boxes and spots. Some people do really well inside, but not me.
Finally, practice, practice, practice. Don't get discouraged, it gets easier.
To bullet point it for you:
and, of course,