Well, first of all, let me validate your "that SUCKS" feelings! I'm sorry. Rejection is never fun. EVER.
That said, having been accepted by DS, and having some MAJOR issues with the titles that are available for newbies to choose from, I will offer this thought: are you really sure you want to try this?
Before the DSrs who've enjoyed a lot of success jump in to defend DS, let me clarify my thinking here. DS, when I was first accepted, let me pick 10 titles to write (or "claim") - giving me one week for each. Fine and dandy, but then they didn't approve my bio for what seemed like a very long time. So that week went by and I couldn't submit - because my bio wasn't approved. OK, that was on me - I should have gotten the bio approved first. Mea culpa.
Then the bio was approved after a long back and forth process (another post altogether, really - neither here nor there for purposes of this post). And now I find I can only claim *3* titles at a time. Hm.
OK, well, that's their prerogative. But when I actually look at the titles that are available - here's what I see:
"Why are there laws to protect employee's rights?" (That's a book. Not an article.)
"What happens when a federal labor law is broken?" (By whom? Which law? Different answers. Again: a book, not an article.)
"How to sell heavy equipment" (Come on, now.)
And these are the better ones. When I first joined, months ago, the titles were things like "How to build a XYZ machine using construction paper and PVC piping" (I'm only marginally exaggerating that one).
And all for the fabulous compensation rate of $15. Per article. MAX. (There are lots of titles that pay half that, too. Although, to be fair, you can also choose the "pay per view" model which - let's face it, with a crowded site plus esoteric topics, your chances of getting fairly compensated roughly approach lottery odds.)
I'm not totally down on DS. I think it's a good training ground, and potentially a good way to earn a little extra cash. And I haven't heard anything about DS screwing their writers, as I have with other similar sites. I just am not sure it's all that and a bag of chips. And that comp rate? Is LOW. Way low.
Now, that being said. If you still wanna go for it again, here's what I'd suggest. Read some eHow.com articles. Read a lot of 'em. Mirror the layout, tone, style, etc. Pick something you know how to do very well as your topic.
Basically, the tone boils down to this for how-to pieces:
Use the implied second-person, active voice, and cut out unnecessary words. In other words, instead of "You take this piece and insert it into that piece," write "Insert piece B into piece A."
Hope this helps.
Good luck!