Trigonometry in itself indeed has very limited use, so I recommend learning trigonometry through encountering applications. Two different types of such applications - a purely geometric one and a physical one.
For the geometric application aspect, it's best to solve difficult geometry problems. I recommend some easy problem books for maths competitions or Olympiads.
For the physical application aspect, you can google up the sine and cosine functions and how the waves are modeled by, say, sin(kx-wt). Very nice examples include basic simple harmonic motion, standing wave, etc.
Note that all suggestions above are my personal and biased opinion :)