Equipment needs for U16 and higher are not much different from U14. The level of tune of the equipment should be higher though and the equipment more finely tuned to the athlete's capablity (stiffness, radius etc). Read more about Ski Boot Fitting.
You may start experimenting with different base bevels now, down from 1 degree, including variable base bevels (larger at the tip and tail and smaller underfoot).
Given the higher level of the competitions, you may now look at carrying two pairs of skis to a race: one preped with overlays for the race, which you leave on the hill and another for warmup.
Do remember that the two pairs of skis should be used equally throughout the season for both racing and training, so one does not feel different from the other. Also, the tuning for training should now resemble the one for race day, so the skis are not all of a sudden too sharp or too fast on race day.
Speed skis (SG and DH) are different... If you have them, keep them at 1 degree base and 2 side and move to progressive base bevels when warranted. It actually is a safety issue here, so be sure to talk to a coach: a too sharp base bevel makes the skis grabbier.
Wax selection is where you can make a difference and start looking at more expensive temperature-specific race waxes and overlays. Don't forget to use these in training as well often, so they don't surprise you on race day.
At this point you should know as much as there is to know about tuning and tools and already have most tools there are.
You can never have too many brushes. You sould try them all. Rotobrushes are a huge time saver, plan to have a few.
Pay attention to the brushes, they will become inefficient after a while, some suggest one season of serious racing for the metal brushes, in the lower leagues, maybe two.
See more about Deciphering Brushes.
For tuning, at this point you are doing most work yourself, even base work. Same routine as the U14.
Make sure the bases are perfectly flat and structured - use files and sandpaper or a tool like the Ski Visions Ski Base Flattener. Not even new race skis come with flat bases - if you have the moneys, get them stone ground, otherwise do it yourself.
Read on for even more Ski Tuning Ideas.