This instructable was written by my maker class students to encourage people to learn to use hand tools.
People often think they need an electric saw to make cuts. All you really need is a simple handsaw in your toolkit. It has many advantages as you do not need to run an extension cord or charge its battery. Risk of serious injury is minimal compared to power tools. This step by step will tell you how to make a straight cut through a piece of wood. It will take some practice but once you get good you might find yourself using a handsaw instead of getting out that circular saw. This is also great for kids to get started on woodworking. You will need:
Sharp saw (if your saw is dull it will be difficult to cut)
A board to cut
Step 1: Mark the wood
First make a straight line on the wood with a square exactly where you want to make the cut.
Step 2: Make a notch
Next pull the saw toward you on the line you marked. This creates a notch to start your cut, if you want more of a notch its okay to do this a couple times. Use your thumb as a guide to make sure the primary cut is parallel to the line you marked.
Step 3: Cut
Then push the saw down with light force on the wood. Make sure the blade is always straight up and down and the blade is not tilted sideways. If you see the cut is starting to go crooked start to correct it by putting a twisting force on the blade and guide it back to straight. You have to keep sighting along the blade and your cut line to keep the cut straight.