If you have stuff in place and functional, I wouldn't spend money to change it... allow them to ruin it first, then replace it!
Now if you need new flooring anyhow... etc... here are some thoughts.
No carpet... it's cheap the first time but not when you have to replace it after every other tenant. Go with a laminate hardwood type product. Looks good and is fairly bullet proof at a low price point.
No vertical blinds. They seem cheap the first time but you'll forever be changing them out, adding slats, etc. Leave the windows uncovered for the tenants to add curtains... or put in your own curtains.
Do the entire unit in one paint color. I forget the finish, but not flat. One of the enamels is "washable"... gives you the opportunity to just scrub the walls versus repainting the entire home between tenants. You don't want painters switching colors for every room, make the entire place one neutral color and call it a day.