It is too hard to make change that way. People won't toss trash on your yard. I have a canopy that I use for my sales. All the clothing goes on tables under it. This way the clothing stays dry, and doesn't sun fade.
Some communities require a yard sale permit.
BIG and bright with big letters and big arrows. Make lots of signs including one in front of your house. Place the date and street name on your signs. Use bright fluorescent poster board on top of cardboard for extra strength in case of winds. Check to see if you can read your own signs as you drive by.