How do I know if I have the right shoes to prevent calluses?

My work shoes are the cause of my problem for getting calluses. I'm also on my feet for 12 hours at work and very active, running around, starting, stopping quick all the time. How do I know the shoes I purchase, are gonna help me prevent calluses? Especially, when they feel comfortable. I don't want them way to big or way to small. What do I do?