I agree that Steven's assessment is right on the money and I have run, hired, fired and managed more sales people then I can even think about at the moment.
It is hard to give you super concrete examples without knowing your business intimately. You know your business, you know how the deals you have made to date got done, you know the players and the technology. Now, you need to teach all of this to the new salesperson. I have seen many sales people fail because they come in and the boss gives them a list of prospects or even an area to check out, some collateral material, a tour of the office and says, "go forth and make money". It doesnt work like that. A successful sales person will need time, your time. You need to train them in your business, in the way that you work, in your expectations. If you dont do that then dont bother hiring one because it wont work out. I know you think you are too busy and the whole reason to hire a salesperson is to not have to do this stuff anymore and 6 months into the relationship great, you can step back but not day 1, or you will just cycle through people.
And commission only is not a good deal for many- you will get someone agressive for sure but you may not get someone who cares enough about your model to make the "right" deals, he will just make "any" deal and yuo will be the one doing the clean up on that. Base + Commission is the best way to go with a sales person- you value them, they value you.