The one piece of advice that I would give would be that no matter what marketing tool you use, keep it up-to-date! One of the problems I find with using online marketing methods (e.g. FB, Twitter or whatever) is that often people will use a “set-it, and forget-it” approach, meaning that they set-up the account and then quite often let it go stale by not constantly and consistently monitoring its content.
Having an online presence for marketing can be great, but it can also reflect poorly on our business or services if we allow it to become stagnant. So I would say my one piece of advice is that “whatever you use, keep it fresh!”
I hope that this helps.