Always place your seed order well before planting time. This will let you experiment to find which cultivar you like best. It's easy to get carried away. The first time you order from a company, keep the order small until you find out how reliable they are and what their quality is like.
Neighbors are usually good sources of recommendations.
Include taxes and shipping charges where appropriate. If possible, make a copy of the order before mailing it to the company. This is valuable if there appears to be a mix-up in your order.