Here are some videos on Solving Trigonometric Equations
Video 1 clearly explains how to solve basic trigonometric equations and also explains the General Solution of trigonometric equations very clearly by referring to the graph.

Video 1
Video 2

Video 2 goes through solving trigonometric equations of the form sin(ax)=c where you need to change the domain


Rarely, but sometimes, you might get a trigonometric equation which is a quadratic in sin(x) or cos(x) and you need to factorize it first. Video 3 explains how to do this.

Video 3

Video 4 is by a Victorian teacher and explains really well the meaning of the general solution for trigonometric equations."Please note a couple of errors. At 3.37 I say that the second soln is 6pi/3. It should be 4pi/3 and the same at 4.04, my first soln is 6pi/3 and it should be 4pi/3." 
Video 4

Video 5 also goes through general solutions and shows how to get the general solutions quickly

