Right at the very beginning, before you collect ANY pages, head slightly to the left, straight ahead of you (using a map from a website will help with this) and go to the 'multiple bathroom' (the brick building that upon entering, has white tiled walls and floors) and find the note in there (if any). Get accustomed with the building and figure out a quick escape route. Grab the note and escape as quick as possible and continue with the game.
The reason for this is because Slenderman can trap you in that building REALLY easy. Infact, almost every time you go into that building he will trap you.
Mod Edit: It should be clarified that Slederman WILL follow you but he will be slow to start and it's just considered ideal to get this note (if it appears there) earlier because he can more easily catch you in the building.
When you see Slender man, he can't move until you turn around and then look back at him again. But here's what you do to keep him in one place and escape him as well. When you see him, line him up in your perspective with a tree so you can't see his face and most of his body. He will remain there, while you quickly back away and run, all while he's stuck in one place. You'll escape quickly and survive too.
Note: If you have 5 pages or more when you do this, the screen may go blank for a moment, during which Slenderman can approach and kill you faster.
When you beat normal mode, You will unlock the easier Daytime mode, Beating that gives you Marble Hornets mode, A mode based off of Youtubes MH Which is a serious of real-life Slender man Encounters.
Beating That gives you 20$ Mode, Where everytime you see Slenderman he sings Gimme 20 dollars. After all, They say he only wants his 20$.
1-If you take to much to find a page, the music will get faster and scarier, and if you don't get the page in a certain period of time, Slenderman will appear in front of you
2-In the last versions of Slender, they've realized that people, when they see Slenderman, look at the floor orr at the sky. So they've activated something that makes your camera shoot directly to Slenderman if you stare at the floor or at the sky.
3-This glitch happens to me, I'm not sure it will happen to you but:
if your screen starts to vibrate, don't press escape. It will cause a loud beep in your ear.
P.S.: Don't do what I did. I wanted to record a video of Slender and I had the tittle screen with the scary music in the headphones, and, while I was editting the record settings, the scary music stopped for one second, and suddently, the beep that comes in the game when he gets you comes into my headphones. But much much louder and annoying.
Have fun playing!