Option 1. You can wait until after the redemption period (6months in MI.) it will be listed with an REO listing agent.
Option2. You can find out when the sheriff sale will take place, then go to the county court house/ or wherever it is held where you are and bid on the property. If you win the bid you will have to wait until the redemption period is over, if the previous owner does not redeem the property you will be able to take possession of it then.
Option 3. After the sheriff sale you can go directly to the bank and make an offer to purchase "The Paper". This is usually only done with cash offers though. Once you purchase the "Right of the property/ or Paper" you will still need to wait until the redemption period is over to take possession. If the owner redeems the property you will be refunded your money.
Option 4. After sheriff sale you can contact bank let them know your interests, make them an offer to purchase before it is listed with REO listing agent, you can use a buyers agent for this step to coordinate the transaction. Usually this is an option if it is a smaller local bank who owns the property.