My ex and I sold our house that was in that price range using one of the for sale by owner sites...I think it was
For Sale By Owner Marketing and Consulting Service but there are several sites out there doing essentially the same thing.
Because of our asking price, we chose to go with the package that included a 1/4 page ad in the print magazine. The package also included being listed on the MLS and I think a street sign. This was in 2006 and IIRC the total cost was about $2K.
I think we intentionally started a bit high on the price, lowered it after a few weeks, ended up with two buyers at the same time (both offering more than the lowered price but less than the original price), chose the better offer, and sold the home in less than a month.
We had bought and sold several homes by that time, so we were comfortable with all parts of the process and doing them ourselves; we didn't need to pay a realtor to coordinate everything. In fact, we sat down with the buyers to fill out the contract and got the whole thing done in about 20 minutes at a Starbucks and it was much easier and faster than the offer/counteroffer process (we did have buyers who were easy to work with).
My advice:
1. Be sure you're comfortable doing all of it yourself - taking pictures, writing ad copy, deciding on a price, engaging with a FSBO site, doing showings, negotiating the offer, dealing with inspectors, doing any needed repairs, dealing with the title company.
2. Pricing was probably the hardest part for us. But if you start a little on the high side, get it into the MLS and get enough exposure, the market will tell you - if you're too high, you won't get any showings or interest; if you're too low, you'll get multiple offers at or above the asking price. I think what we figured was we could misprice by $10K and still come out ahead rather than pay $20K to an agent. The other thing I would do now is objectively go look at some houses for sale (either online at realtor.com or in person) in your price range. You'll get a sense of what your house is worth that way: "Oh, that one is the same size as ours but 5 years older and they're asking $399K" "That one has an extra bedroom and a walk-in master shower and they're asking $449K"
3. Consider offering half of whatever the normal commission is in your area to any buyer's agent. Buyers' agents generally won't show your house to their clients if there is no (or reduced) commission for them or if they have to negotiate something with you. I think we did this and it was fairly standard at the time. I don't think we ended up paying it though because our buyers happened to not be working with an agent either.
4. We did use a standard "fill-in-the-blank" contract that our state uses. Since we had been through buying and selling several houses, we already knew how to do that, and the actual physical contracts were provided for free by the FSBO place.
5. As hinted above, I would suggest picking an advertising/marketing package that is appropriate to your home's sales price. The FSBO place would have let us try to sell our house with a one line text only ad, or a full page color ad. Look through the FSBO magazines and use common sense and you'll be able to figure it out.
The main pitfall I would avoid is any sort of non-standard or ambiguous contract language. Talking in person with the buyer and hashing out the language together helps minimize or avoid this.
Another one, I guess, as mentioned by PP, is to avoid problematic counterparties (buyers in your case). Everyone we've dealt with has been fine, but I know they are out there. If you get the sense that you're dealing with one of these, the easiest thing to do is to turn down their offers or counteroffer at a higher price so they pay you for dealing with the hassle (can be hard to assess up front; guess high).
Good luck!