Hints:

In adventure games, pick up everything you find. It might be useful later.

Try combining items in inventory.

Try everything on a puzzle, even though it seems ridiculous.

Explore everyplace possible. Draw maps as you explore!

Get all information possible out of each character you encounter.

Sometimes, no matter what you say, you get in trouble. Choosing the wrong response can even end the game.

Save before entering a possibly dangerous situation and after completing a task.

Save after long cut scenes or movie sequences. If you have to reload, you don't have to watch the whole thing again.

Save before talking to major characters so you can alter your conversation if necessary.