If you do a search you'll find plenty of info on this, but i'll highlight the general consensus.
It is not impossible, but very, very, very difficult. I believe 3 DO's matched in the 2007 allo match...there weren't any this year.
Crush the boards, the average match score was 236, so if you're a DO, you might want to be hitting close to 250
.
Research never hurts.
Rotate and kill the rotation at the site you're interested in.
Get great LOR
I'm not a NS resident, but am leaning in that direction. Not all the DO programs are sub-par, so don't write those off. it's not going to be an easy road if you are only considering allo; it's not going to be an easy road if you are only considereing osteo either. hope that helps