#1 - Be professional. If you are going to be setting up your own business profiles then understand it will represent your business, not you. Keep this in mind when writing and selecting a photo. First impressions are usually lasting ones!
#2 - Be involved. Don't just hand over access to your profiles and accounts without really testing a marketing company first. Set up some blind accounts and see how the company handles them. If you are satisfied, hand over the reigns to your company but closely monitor your accounts.
#3- PPC. Don't know what this is? You should. PPC is Pay-Per-Click advertising and there are two very different schools of though on this. You need to do your research, know the terms, know what results should look like, and know how much everything will truly cost!
I will be posting more on internet marketing through the week. Feel free to send me your questions via Twitter!