Welcome!
I think the most important thing to think of for planning a scrap quilt is contrast. Lots of patterns for scrap quilts specify "light" and "dark" fabrics. If you use any "medium" contrast fabrics, then you will need to consider more carefully where to place them. Some multicolor fabrics are difficult to deal because some parts are light and other parts are dark, so you also have to consider those carefully. One thing you may wish to purchase is a tool to help you see the contrast better. There are some red and green plastic transparent pieces that can help.