Take Notes
Taking notes on a game is almost unheard of these days, but it was a common tactic back in the day. "Riven" gives you a lot of information, and some of it is not understandable when you receive it. Therefore, it can be difficult to keep everything straight unless you write everything down. Keep a notepad and pencil next to your computer and take notes on every puzzle and item you encounter. This will help you remember where the puzzles are located and may provide a clue as to the other puzzles you'll encounter in the game.
Look At Everything
The scenery in "Riven" isn't just scenery. Puzzles, clues, required information or needed items are often built directly into some of the massive set pieces you'll come across in the game. Examine every bit of scenery you come across, especially if it looks like a machine or something that might be movable. Many of the puzzles in "Riven" are centered around pieces of machinery, and the "Boiler" puzzle on Crater Island is an excellent example of this. Its water control wheel and boiler activation switch are actually vital parts of the puzzle.
Bring a Calculator
Many of the puzzles in "Riven" are based around math and math equations or patterns. If you are not a particularly math-savvy person, a calculator can be an invaluable tool to help you solve some of the more complicated math puzzles you'll come across in the game. The Number Sequence puzzle in Catherine's Journal, for instance, requires you to complete a number pattern in order to access other areas of that particular part of the game.
Make a Map
You should also make a map of the game world as you play through the screens. "Riven" is a large game, and you will need to revisit several areas you've already seen as you progress. A map will make it easier to find your way back to those rooms, and it will also keep you from getting lost in the maze-like areas of the game.
Save Often
You can die in "Riven," and not every event that leads to your death is immediately obvious. Save your game often, in different save files, so you have several points you can return to if you make a wrong turn or pull the wrong lever on a certain puzzle.