I definitely agree 100% with trying to get some neighbors involved! I am actually going to be walking my street this week to let neighbors know I'm planning a yard sale on Apr 17th. Community/Multi-family Yard Sales always attract a bigger crowd of shoppers because there is more chance for them that they will find things they want/need.
I will post a sign in my fron yard a couple days before the yard sale and will post them at the ends of my busy street the night before. I will also advertise on craigslist. If a couple neighbors join in, I will ask everyone to pitch in $1 or $2 to place an ad in the local paper and pennysaver. If you have any small neighborhood businesses, they may allow you to put a flyer in their window also.
I wear an apron (got some from home depot for free) and keep money in there. As I get bigger denomonations of money, I will put them into my house, just to be safe. Make sure you have plenty of ones, fives and quarters for change.
I can't stress how important it is to put prices on items and to organize them! I buy a pack of the little dot stickers from Walmart (they cost like $1) and I put a sticker on every piece of clothing and just about everything. If I can't put a sticker directly on an item or its an item that has several pieces, I put the item in a ziploc bag and write the info on it (ex: 10 prs infant socks $1). For things like rattles, bibs, etc I had a bin and taped a sign onto it that said "$1 each or 7 for $5).
Be ready to negotiate, especially if people are buying a large quantity of items. I had 2 yard sales last year, at the 2nd one I had a woman come about an hour into it and asked how much for my entire table of baby clothes. I told her the price, she accepted AND she bought a bunch of other items I had also! I ended up giving her some things for free simply because she was buying so much and it was encouraging her to buy more - I certainly didn't want to pack the stuff back up and store it, and I needed the money.