I have built several bookcases over the years. They weren't made using technical plans or expensive tools, but they are sturdy, look nice and hold all my books. They are certainly much higher quality than the low budget bookcases I've seen for sale in discount stores. They are usually made of a cheap pressed board which has little strength. Mine are made from solid wood.
The only tools I used when building my first bookcase were a jigsaw, drill and hammer. If you find that you need more space to store your books, you can easily build one yourself. There are a few things you should take into consideration before you start.
Solid Hardwood Bookcases
First you need to decide how long and how tall you want your bookcase to be. You can build it tall and narrow, low and wide, or you can build a very large storage unit. Just be sure to measure the space where you will be putting it when finished. You can build it to sit on the floor or hang on a wall. A size of 3' tall and 5' wide makes a nice sized unit for a beginner. It's large enough to hold around 150 paperbacks, if it has 3 shelves. If you line books on top and use bookends to keep them upright, it will hold even more than that.
If you plan to hang it on the wall, you will need to buy sturdy brackets. I recommend a minimum of 6 brackets if your bookcase will be very large. Place 2 on the top, 2 on a center shelf, and 2 underneath the bottom. The easiest way to go about this it to mount the brackets on the wall, then lift the bookcase into place. After that, attach it to the brackets with wood screws. It's best to have someone help you hold it in place while you do this. Be sure that the brackets on the wall are screwed into wall studs. Walls studs are normally placed 16" apart, but not always. You can find them by using a stud finder, or by the old fashioned method of knocking on the walls. When knocking no longer produces a hollow sound, you have found a stud.
The next step is to made a decision on how deep your shelves will be. The wider lumber is, the more you will have to pay for it at the home improvement store. Shelves 6" wide will do quite well for storing paperback books and smaller sized hardbacks. If you have a lot of larger sized hardback books, you may want to opt for 8" or 10" lumber. Whatever you decide, you will need to purchase the lumber for the sides, top and bottom in the same width as the shelves.
Measure the tallest book that you own. This is a bit of advice that I can't stress enough. Knowing the height of your largest book will help you decide on how far apart to place your shelves. Take the height and add at least an extra inch of space between shelves. If you have room, add an extra 2 inches of space. Make sure at least one of your shelves has clearance to hold your larger books.
I have found that as time passes by, I seem to accumulate taller books. I've had to build more bookcases special for holding them. If you leave enough clearance to start with, you can avoid this problem. The other shelves can be placed closer together, if you have mostly shorter sized books.
If your bookcase will be 3' wide or wider, you should plan on building at least one support somewhere between each set of shelves. This is easiest to do if you stagger their placement, and don't try to place one directly on top of the other. If you don't use supports between long shelves, they will eventually begin to sag from the weight of the books. Just cut a support board the length of the space where you will be placing it. For example, if you have a 7" clearance between shelves, cut the support board 7" high.
You can use any type of lumber for your bookcase. Pine is the cheapest and will do a great job. Poplar and oak are more expensive but will make a more professional looking piece of furniture. You should be able to find all three types of shelving boards at any home improvement store.
A circular saw will be easier to use when making straight cuts, but with care, they can be done with a common jigsaw. Do be sure to drill pilot holes in your lumber before nailing it together. This will help keep the wood from splitting. Make sure to use a drill bit that is a size smaller than the nails you are using. Use finishing nails when assembling your project. I used 6 penny finishing nails on all of my bookcases.
Once you finish assembling the sides, top, bottom, shelves and supports, you may want to sand and stain or paint your completed project. It isn't necessary, but it will help make a finished bookcase you can be proud of.