George, I would recommend reading David Greene's new book "SOLD". Chapter 2 speaks of choosing a brokerage.
Some things brokers will say that may not be important for now are:
"strong brand in the community". Buyers/sellers are choosing YOU to work with, not the brokerage.
"We are the cheapest option" This is like saying you are the Walmart of the industry. You get what you pay for.
"We can build your brand" They may assist, but won't do it for you. As a brand new agent, your focus should be on actually learning the business and training rather than brand building your brand at the very beginning. Learning the business and training will build confidence, and nothing else is stronger at building a brand than confidence.
"We have technology nobody else does" Every brokerage says this. Many clients won't even use the technology provided unless it's really good. Most of your clients will just choose a listing they like and ask you to arrange a showing, then maybe write an offer.
However, things to look for and ask are:
Training: Hardest to find but most important.
Support: Ask who, specifically, will help with writing offers, filling out forms, navigating MLS, and dealing with the various scenarios you will encounter as a new agent. Brokers will tell you they'll help with website and business cards, but won't offer assistance in getting your first client under contract or negotiating request for repairs. Prioritize practical support over fancy marketing bells and whistles.
Enjoy your new career