If necessary, cut background board to desired size. Cut or tear paper and other elements, then lay them out on your board. Papers also can be folded, fringed, shredded, crunched, or pleated.
Move the pieces around until you're happy with the layout. Don't glue until you're satisfied; ripping up leaves a mess of uneven debris on the collage (If you end up not liking something, cover it up!).
Brush glue on the paper with a paintbrush. Small bits require a small brush; with larger pieces, a 2-inch brush is more effective. If you're using colored tissue paper, spread the glue on the board first and put the tissue paper on top of the glue. Use the same technique if you want to glue down small seeds, tiny beads, or fragile leaves: Spread glue on the board, sprinkle tiny things, and pat down carefully to adhere.
As you paste down any paper, start on the center of the paper and press to the edges, squeezing out any air.