THE demise of the slide show has been forecast for more than a decade, yet it remains one of the most effective presentation mediums in the meetings industry. I suspect it will be for a long time to come. Slides are cost-effective to create and project, and are portable. They present a considerably sharper image than does video, and the projectors continue to improve.

Bad memories may linger for anyone who's ever jammed a tray with a damaged slide, projected a slide upside down or backward, or watched his or her audience try (or not try!) to fight off a nap once the lights go down. But there are solutions to many of these problems. Here are 13 tips for avoiding presenters' most common mistakes.

Slide Show Solutions * If you use an infrared remote control, make sure that your workshop neighbor isn't using one on the same frequency. Often the air-walls will not keep your neighbors from advancing your slides-or you from advancing theirs. When in doubt, use a wired remote.

* Make sure the screen area is dark, but the room doesn't have to be. Recessed ceiling lights can be kept on, but chandeliers, sconces, and other lights that wash on the screen should be turned off, not just dimmed. Don't forget the reading light on stage. If necessary, tape a piece of cardboard to the edge of the lectern to block the light.

* If you have a problem with high ambient light, make sure your screen has a beaded surface (assuming you are not using rear projection) and consider a brighter lamp. An EXR lamp, standard for an Ektagraphic III, lasts about 35 hours and is considered 100 percent brightness. You can replace it with an EXW lamp and get 120 percent brightness, but the lamp has a life of only 15 hours. The next step up is to use a special lamp module (casing), which will give you 150 percent brightness.

* Remember this rule of thumb: The first row of viewers should not be any closer than two times the height of your screen; and the back row should be no farther back than eight times the height of your screen. (If, for example, you had a seven-foot-square screen, the back row should be no more than 56 feet away from the screen.) The bottom of your screen should be at least four feet from the floor. This keeps the visuals above the heads of the audience.

* Glance at the screen to make sure the correct slide is up, but make sure to face your audience when you speak. A fixed podium mike won't pick up a voice unless the speaker faces forward, and even a lavalier mike fades a bit if the speaker's back is to the audience.

* When using front projection, place the slide projector behind the audience. This way the machine can be placed higher (near optical center) without blocking the audience's view, and it also helps keep the fan noise away from the crowd.

* Don't mix mounts. Sometimes a projector's autofocus mechanism cannot adjust between glass mounts and plastic or cardboard mounts. It's much safer to have all the same mounts.

* Keep your slides clean. It's counter-productive to spend money on beautiful slides and then have them covered with dust. Keep your trays in their boxes or keep their covers on.

* Use 80-slot trays. The 120-slot trays tend to jam.

* To load a tray for front projection, place it in front of you on a table with the 0 slot at three o'clock and numbered slots (1, 2, 3, and so on) coming toward you. Hold the slide up and view it as it should appear on the screen. Holding it by the left bottom corner, cartwheel it into the slot. The bottom left is now the upper right. For rear projection, instead of a cartwheel, dive the slide into the slot just like going off a diving board. The left bottom corner becomes the left upper corner, and the side of the slide you were looking at ends up facing away from you.

* If you have a presentation that isn't updated often, number your slides and try this: Take the slides out of the tray, in order, and still upside-down. Hold them tightly together in a small box and, with a black marker, run a stripe down the left side of the tops. Then, with a red marker, draw a diagonal stripe from the upper left of the first slide to the bottom right of the last slide. When you put your slides back into the tray, you can tell if they're all turned the right way (for front or rear projection) and if any slide is out of order.

* If you have an especially short projection distance, ask about renting a perspective-control lens, which can make up for the problem.

* If you need a spotlight at the last minute, put a circle mount in a slide projector with a zoom lens and get some light on your VIP.