Kodak Elite Ektachrome is recommended. Set up artwork against plain background. Always, Always take slides before you put works under glass. Look at the slides with projector and screen. Never send out a slide that you have not projected.
Some slides needs masking to cover a busy background or wall.
This is the time to avoid discount chains. Labels for slides can be purchased at any office supply store. The label should include your name, title of artwork, date, medium and size. When noting size height precedes width. Check out the College Art Association's guide to slide labeling.