Yellow glue and clamps. If you joint your edges true then you really don't need any other form of mechanical bond other than the glue joint itself when glueing along the grain. If you're deft with handplanes, the best joints come when the edges are hand-jointed true; this is best done with both edges at the same time, as this would produce recirpocal angles if you didn't shoot the edge exactly 90 degrees. Though if you used a shooting board, they should be pretty dead-on...
Next best glue joint would be with a jointer, though you have to set it so you don't leave toolmarks. You could also set up a router table with a special fence for jointing on the "flat." A tablesaw glue joint is fine for production work, but in my opinion not good enough for fine work or presentation work. You'll always get a telltale glue line.
Either way, you'll have to hold the joint up to a strong light and see if any goes through; if light does pass you havev some work to do.
Sanding is the least desirable way of fitting joints since it tears the wood fibers, making the joint weaker. I routinely join the tops and backs on acoustic guitars, which are only 1/8" thickness or less. Done right, you'll break the wood before the glue joint.