What other tools do I need with my truing stand?
If you're just truing a wheel, all you need is the appropriate spoke wrench (which depends on what wheel you have, obviously). 

There are four aspects to truing a wheel (quoted from Park Tool, which I suggest you read): 


  LATERAL TRUE: this true is also called “rim run-out”, and is the
  side-to-side wobble of the rim as the wheel spins. This aspect is the
  most critical to brake caliper settings.
  
  RADIAL TRUE: this is the amount of up and down wobble. If the wheel
  becomes out-of-round, it wobbles up and down with each revolution. In
  severe cases this will affect brake pad placement and can be felt by
  the rider as a bump every wheel revolution.
  
  RIM CENTERING or “DISH”: this refers to the rim being centered in the
  frame. If the rim is offset in the frame to either side it may be
  difficult to adjust the brakes. Severe cases of poor centering can
  also cause handling problems, because the rear wheel will not track
  behind the front wheel.
  
  TENSION: this is simply the tightness of the spokes. Spokes are
  tensioned just like other fasteners. Spoke tension is best measured
  using a tool called a spoke tension meter (tensiometer) such as the
  Park Tool TM-1, which flexes the spoke using a calibrated spring.


You probably won't need to handle dishing a wheel at home. As for the tensiometer, it can be nice to have (esp if you're replacing spokes or whatever; large deviations from normal spoke tension) or if you get into building a wheel, but a lot of people go by feel (squeezing spokes or whatever) and it is adequate.