Yep, absolutely, everything Debbi said. It is about having fun and helping yourself and others at the same time. It is a jog, to be sure and one that has to be prioritized. Most of my tweeting, facebook and blogging is done at night somewhere between 10 pm and 3 a.m. During the day, I work on my jewelry or I am working on a crochet project.
You just have to figure out where everything fits. I can tell you that the more you promote, the more you will get out of it. It does help. I have not had sales yet, but I am getting comments and emails about things all the time, so I know that people are seeing my things but they are also seeing sometimes more of other artists work than my own. So I know I have to get more done and photographed and on the site and shop.
Good luck and tweet as you can, I am not a master here just helping out with promotion.
Please post your tweet url so I can put you on the list.