Another option is to volunteer at a place that does free tax prep for low income households. They train you for free and you can basically set your hours.
Here in Michigan the Accounting Aid Society is the biggest but I'm sure there are others.
While it isn't paid it can be very rewarding. I did this for a couple of seasons and while getting my accounting degree. Great experience if you want to someday be paid to do it or just rewarding to help people out that really need it.
Last year I was an assistant manager (paid, $12/hour) at our VITA site after a season as a volunteer in 2012. Based on the number of amendments we do for things that are completely wrong from H&R Block, Jackson Hewitt and (the worst offender) Liberty Tax, I would never work for them. I don't know what kind of training their associates go through, but they're lacking something in quality review or initial training because I see a lot of absurd mistakes and I haven't even been doing it that long.
Your location & the sponsoring organization for your VITA program will determine a lot about what kind of returns you see and level of complexity you take on. VITA has some overarching rules, like no rental property except for military members, no adoption credits, no energy credits, etc. At my site in Chicago, which is one of the busiest in the country, we do just about anything else, including depreciation (we were a pilot site for this last year) amendments, Schedule C's, etc. A lot of the other tax sites from our suburbs refer clients to our site when they encounter something "complicated" like an amendment. I put that in quotes because a 1040X is not rocket science by any means.
But what I'm getting at is that I'm lucky to work somewhere where we get to see all kinds of clients, but it's probably not quite as interesting in most places. And of course, you can expect to spend your first year doing pretty basic returns and slowly build up to doing more complicated ones. I personally spent a lot of time my first year just watching our experienced volunteers do complicated returns & a lot of time in the off-season reading the IRS pubs & sites like Bogleheads to learn the ins & outs and was able to get certified as an advanced tax preparer for my second year. If you want to see what tax prep is like, VITA is a great (and free) way to get started.