1. Pricing strategy: since you already certain about your price, you can use your own as standard, ask for CMA and see if the agent's opinion is inline with yours.
2. Marketing strategy: what is the target marketing audience? Almost all realtors belong to MLS syndication. So, once your property is listed on MLS, it would automatically syndicate to all major websites. So, what will your agent do specically for your property to make it more attractive?
3. Netiogating skills: this is a little hard to convey but you need to talk to your agent to find out which agent is good at negatioate the best price for you.
as for the speed to sell, you can ask both agent to do "pricing to days on market" analysis and decide yourself base on your location.
Hope this helps. Again, this is just my personally opinion, may or may not suit your spefic proeprty and market location.