Kind of late to the party if you are working on starting your own practice now.  E-filing is just a little over a month away and you are going to be pretty much dead in the water unless you have already obtained an EFIN.  No EFIN, no efiling.  The process can take up to a couple of months so if you don't have an EFIN, you might want to drop everything you are doing and start the process now.

You don't say what kind of experience you have.  If you have been working for another tax practice for years, that will help in your marketing attempts.  But if you have been a toll booth operator for the past 10 years and were working as a forklift driver before that, marketing is going to be a little more difficult.  

Greta doesn't accept credit cards.  I do, but that is due to the changing environment where younger clients don't carry cash and have no idea what a checkbook is.  I started accepting cards a few years back.  But for those that want to use plastic just to build up their reward points, I'm not taking a discount just so you can be rewarded.  I charge a convenience fee for me having to get nicked by third parties for processing that plastic.

Good luck.