Here are some basic tips to style the shelves in your space:
Tip#1 - Start from scratch: First of all start by collecting all the items, that you wanna add to your shelves, onto one place. This will help in visualising everything as a unit. Tip#2 - Books: Books are a great way to start decorating your shelves. vertical, horizontal, at an angle, in a stack or grouped by color...there can be endless ways to decorate with books. You can also add bookends to create drama.
Tip#3 - Layers: Adding items on top of each other, stacking things together makes an interesting visual. Tip#4 - Vary heights. Add items with varying heights to keep the eye moving.
Tip#5 - Contrast: Keep the colors of your items in mind when grouping them or placing together. Keep dark colored items in front of lighter backgrounds and vice versa. Tip#6 - Memories: Momentos & personal collections are an important part of shelf decor.
Tip#7 - Space: Don't over stuff the shelves. Keep empty spaces in between items. It helps in making the decor look clean. Tip#8 - Size doesn't matter Do not clutter the shelves with too many tiny small objects as they will only end up fighting each other for grabbing the eye balls. Fewer but larger, well-placed items will create a better look. One last thing - take a few pictures with your phone to give you a completely different perspective. It will also help in eyeing any quick changes.