Do not refer to them as subs or substitutes. Call them a guest teacher, or just, teacher. Many hard working subs feel they are under appreciated. And that they are just there to babysit. Your students will feel this way as well, and treat the sub accordingly. Do you expect anything different?
Your school should bend over backwards to help them and make them feel as if they are part of the faculty, even if it's just for one day. The principal should introduce themselves and make a note to pay a visit to the classroom. The office staff, who will be the goto persons for subs, need to give out all information the sub needs. From bell schedule, to recess duty. Where are the rest rooms? Lounge? Supply room? Custodian? They are walking into a new situation. They cannot be expected to just ask and ask and ask. They should be given all information they need to be successful. If the secretary does not do this, it is up to the individual teacher to leave this information.
This much needed information can be in a sub folder, complete with emergency lesson plans and schedule. This folder needs complete information about the school, including how you line your kids up after and before recess, lunch, etc. Make sure they know where all books, paper, etc. are located.
Leave lesson plans that a sub can actually do. It can't be a regular day, and go like you were there. Adpat your plans. Think about how YOU would like lesson plans to be if you were a sub teacher. This does not mean a babysitter. You should do as much regular work as possible. Be sure and explain all opening and closing procedures, attendance, and the like. A sub folder is perfect for this, so you won't have to write it down each time. But keep it up to date!
Subs need information that may be special for the day...like fire drills, library visits, assemblies, etc.
Inform the teachers next door that you will have a sub and please introduce themselves with a willingness to help.
Leave them a present...like a snack.
This next one is taking a chance, but try it. Leave a survey for the sub to fill out at the end of the day. Ask for ways to improve the sub experience. Sure, they might rant, but the sub life is not a bed of roses.
If you get a substitute teacher that you love, request at the sub caller desk to send them next time! They love this! Being familiar with the school already helps
Become a sub yourself. If you have summer break days when a nearby district is in session, sign up! The more you know, the better you can prepare for a sub.
If you already have been subbing before a regular teaching job, then you already know what makes a good day for a sub.