Buying accessories can be tricky. You might start to over think and resort to buying things that match. Just relax! Have fun! and reach for things that you are drawn to; items that fall within the style of the space. Purchase accessories from different stores; my personal favorites are: West Elm, Target, and just recently H & M. The amount of accessories needed will depend on the style of the space and what you or your client want to achieve. Books, are a perfect filler to create a balance between all of the objects. A great source for books is Books By the Foot; you can buy by color, style, and many more options.
I hope this information has been helpful. Need more inspiration? Visit my Instagram page on the upper left for accessory inspiration and how to place them. Now get out there and find accessories that will make your space feel lived in and add character.