Great questions. Most townhomes don't work good as rentals due to the HOA dues. Not that there are really a lot of townhomes in Carrollton anyway.
I see lots and lots of different strategies work, but what I see best work is 3bed/2bath/2car garage that's not too old, but as low a price as you can get and that should rent in the $1200-$1500 range.
There are always exceptions. It can depend if you can pay cash or are using financing. If you can do rehab or want a move in ready product, and how much money you want to spend.
The other thing is that I would not limit yourself to Carrollton. Richardson for example might be a good place to look. Occasionally Plano might work....there are other cities that might work as well. Right now I like Denton. Lots of pressure there, low supply of rentals and good demand.