Most of us hoard our gems for special habitats or animals that become available or go on sale. Early on in the game, a lot of players don't realize that it gets harder to earn gems as you increase your level. The game eventually stops offering all those "try this game" bonuses, and if you're not willing to pay actual money for gems, it takes time and patience to collect enough to buy anything good. ;-)
I've gotten 7 or 8 gems a day when I've had lots of good gem buddies. Every once in a while it's a good idea to throw a few random gems out and try to cultivate new partners. Of course, it's nice to find people here in the forum too. :-)