I’d actually recommend starting it earlier than that… Serious garage salers are out in the wee hours of the morning to try and get the best deals… Make sure to have multiple signs posted with your address, and maybe highlights of what you have… You might consider doing 50% off the last day to try and get rid of whatever is left; if you do, drive around to the signs and mark that on there the last day… Be open to “haggling”, it’s better to sell something for less, than to have it sit. If you can get a couple neighbors in on it, that’s even better, people prefer going to multi-family sales for a wider selection. Call your other friends and families and see if there are any items they want to sell, even if it’s just one bike, or one crib, or one stroller. The more things in your yard, the more likely people will be to stop. (For me, I hate clutter so I never accumulate enough to ever have my OWN garage sale, but I would gladly “piggyback” on someone else’s and sell a few things here and there… and give a small percentage of the earnings for their time.) Go to the bank and make sure you’re going to have change before the sale starts. Try the grocery store trick for increasing purchases: for example, price clothes for $1 a piece, but make a sign advertising 10 pieces for $5. People will see they’re getting a deal if they buy more, and they’d be more likely to look a little harder at things to get to that “magic number”.

All the garage sale shows recommend not taking the stuff back in the house after the sale is over. Load it in the car and drive it to charity immediately, or arrange for a charity to come and pick it up at your house.

I did one about a year ago with my Mom and it was not fun nor did we make much money. People just nickel and dime you. I now just give my stuff to charity which I can write off on my taxes. That may not be a benefit for your father though.

Nevertheless I do wish you success.

You really need to have a bunch of stuff to make it worthwhile, and big things that can be seen driving by. If there’s just a table or two with knickknacks, people aren’t going to stop.