if you can get help from family or friends, that will save you time and energy.
be nice and courteous to all customers, even the rude ones. try not to get too greedy. if you are offered a reasonable price, then take it, or you might not end up selling a lot of items. any price is better than none.
some states only allow you to have two garage sales per year.
close to the end of the sale, mark everything half-off or even free to get rid of items. 