When I was just starting this junk journaling /collage thing, I was often overwhelmed by the sheer number of possibilities there are. Do I use stamping? painting? papers? stickers? The blank page can be a bit intimidating.
I started using a 3 step formula for collage that works really well for me. I just mindlessly do these 3 things, and I suddenly have the whole page covered in a neutral background and I have a little frame around it and I find myself ready to create.
All of the collages in this blog were started the same way. If you look, you can see the steps in the background. I show both rectangular and square versions.
Take two corner sections of an old book page and use them to define two opposite corners of the collage, leaving an equal outside margin. I use Mod Podge and a brush to glue them on.
Add a piece of tissue to the center. I used gift wrap tissue that I had printed on. Here is a link to how I did that. How to Print On Tissue Paper
You can also use a tissue (separated into 1 layer) or just plain uncolored gift tissue. It can be wrinkly to add texture.
Use a neutral sticker corner piece ripped into a diagonal to cover remaining corners, again, leaving an equal margin to make a frame outside the collage. If you don't have neutral stickers, you can use any neutral cardstock or paper you have with a 90 degree corner.
So now your page has a nice frame around it. You can choose to stay within that frame or not as you collage. (I usually do not, if you look at the examples to follow.) You have covered much of your "blank page" and can get on with the fun of creating. Go for it! A video explanation of the process is here: Collage Jump Start Video
When you feel like you are almost finished your collage, put it away. Consider it your "rough draft," just like in English class. When you look at it in a day or two, you will likely see a few things you want to change. If not, consider it done.