How do you search for property in foreclosure on via Sheriff's sale?

It's usually done late August in Mississippi. The Sun Herald will run a section earlier in the summer with a list of tax auctions. Since it includes the legal descriptions you'll be able to quickly identify the large tracts of land.

Downside is the owner has to not pay for three years before you can claim the parcel. If they redeem during that window you get 18% annual interest as a nice consolation prize.

For bank foreclosures, every county is different. Sometimes it's in a local newspaper, others have it on the county website. Some have auctions on almost a daily basis, while others do once a month.

Caddo Parish Sheriff's Sales

Here is the link to the calendar for sales in Caddo Parish. Sales are usually every Wednesday, but I believe they still require in-person bidding. Toggle the the "show details" trigger for info about the appraised value if that was a requirement in the foreclosure suit. You can also find the suit no. for the foreclosure if you want to dig even deeper. You could also call the firm that filed the suit to find out more and potentially even make an offer for a short-sale.

ETA: I agree that every parish likely has their own way of doing this, just giving you an example I'm familiar with.