The first question that might come up when starting out on Myst could be "What Age should I do first?" Well, generally it doesn't matter, except for one thing: DON'T do the Selentic Age before the Mechanical Age. The Selentic Age has a maze that uses information gathered from the Mechanical Age. If you mess up on this, prepare to bump your way around the Selentic Age for at least two hours. Don't do this!
This is a tip for anyone who doesn't understand what Atrus is talking about when he mentions tower rotation. Follow these steps:
1) Go into the library. DO NOT FLIP ANY SWITCHES!
2) View the map next to the doorway. You'll see a map of the island, with one building already visible on it. What could that thing be behind it?
3) Go outside, walk a little distance away, and view the library. Yes, young grasshopper, that's the tower.
4) Go back inside, find the painting that shows a secret passageway behind the bookcase, and click it.
5) Follow the passageway, get in the elevator, and go up. You should be facing a ladder, the other one is behind you. This'll come in handy later.
Now, go around the island, flip all the switches, and come back to the map. Other objects will have appeared. Hmm, maybe holding down the tower picture will help...