Have bought and sold outside of manufacturer. Be open and realistic about your expectations. If you are looking for a specific price let people know so you don't get a bunch of lowball offers. At the same time realize that even if she is in perfect condition it will be hard to get what you paid for.
If you don't have paypal get it setup. It is a decent way to transfer money. You could also use Western Union as an alternative but they charge for money transfers so paypal is probably better.
Also figure out whether you want to deal with international shipping. If you do you may want to factor in the extra costs in your sale price. I've only done domestic deals because it is less hassle.
Take a lot of current pictures also. Especially of any damage areas. This is so you can have more pictures to show anyone that is interested. It is also for your protection. Recent pics and pics of the packing process protect you from any funny stuff.. like the buyer getting the doll then coming back and saying her arm fell off or something.
Selling a doll isn't difficult at all. Just know what you want from it and get everything ready so you can ship her out in a decent timeframe after getting paid. Good luck.