Things I find helpful
Advertise on Craig's list
Price cheaply but not so cheap you are not willing to deal everybody will ask for a lower price.
Hang as many clothes as possible and have a blanket price on them ie all jeans $5 all button down $2.00 dresses?
Put breakables, anything you think is worth more and electronics on tables.
Try to group like items together kitchen item, linens, kids toys and games, electronics.
Anything you want more than $5 on put a sticker on it.
If you are selling functunal electrical items, toasters, radios, fans have a power cord available so you can show how well it works.
Day of sale have a lot of smaller bills 1's 5's 10's even a 20 or two that way you won't loose early morning sales or have to reduce your price because you don't have change.
Good luck have fun I'm sure you will get a lot more tips and ideas.