One of the most daunting tasks in building a uke is creating the bent side pieces of the body. I have done it with two different techniques, both of which give good results.
Different woods have vastly different bending characteristics; expect to break some pieces while you get the hang of bending. The thickness of the sides should be between 1/16" and 3/32", give or take. Make sure they are sanded pretty good on both sides before bending - it seems like cracks form more easily at saw marks...
If you don't wish to invest in any special bending equipment, go with the cold method. All that's required is a two-piece wooden form, and quite a bit of patience:
The form is several blocks of plywood glued up to match the width of the sides you are bending. Trace the outline of the side on the block and cut it out. Then cut (or sand) a bit more off the male half to accommodate the thickness of the side material. (If you haven't got a band saw, cut the layers separately before gluing them up.)
Soak the side pieces in water overnight. Clamp the male half of the form in a vice and carefully press the wet side piece over it with your hands, making sure that the wood will actually bend without breaking. Once satisfied with that, press the female half of the form in place, using a bar clamp if needed. Fasten the two halves together with masking tape, remove the clamp, and set the entire thing aside to dry for 24 hours or so.
Before taking the form apart, trim the ends of the side panel with a knife or fine saw. Use the edge of the plywood form as a guide to get a nice square cut.
Even after 24 hours, the piece will not be fully dry, so you'll need a second form to hold the sides in shape while they dry completely:
The cold method works just fine, but if you want to speed things up you'll need to apply some heat. Either buy a commercially available side bender, or make your own. Here's one I made out of scrap metal, heated by a light bulb:
Again, you soak the wood in water, and then form it over the hot tube while wearing heavy leather gloves. You'll also want a plywood template (like the male half of the one above) to check your progress, and you'll also need a form to hold the bent sides while they dry completely:
(Pineapple shape sides shown)
Next: Neck & peg head
If you find any of this helpful I'd certainly appreciate a "tip" :-)