Make sure you use the eyeglass regularly to check things as it will sometimes reveal something you have missed.
Hint System
Use the hint system when you find you are stuck and need a bit of help. The first couple of hints that you get are never explicit.
Various Tips and Tricks
Keep in mind that the only things you can interact with are the things you can zoom in on.
Use eyeglass to check things with regularly, they usually reveals something you've missed.
The hint system is very handy if you're stuck, and the first couple are never explicit.