Hi reznor, which file are you using?
I print as many things as I can on a flat surface. Don't get sucked into thinking you have to print everything out whole.
Whatever file you are using, try slicing it completely in half horizontally. Then you will have a fully flat back to print out on.
I would suggest using a pritt stick (the one that came with my Da Vinci worked really well, so I bought a whole bunch of them, very cheap) and covering the area that you will be printing. This helps to prevent warping.
The da vinci software is fine for good basic work like this provided you do a bit of pre model work - a program that is very useful is Netfabb Basic - download that, and it will let you modify and cut your models (and fix them for any small issues) for free.
Remember, ABS is great for post process. It can be melted down or smoothed with acetone, and you can then sand that down again.
Always remember that printing is a great way to get a quick base for a prop, and never expect perfect finished results - unrealistic expectations are usually what put people off printing when they start :thumbsup
