These videos are a little boring however, they clearly explain the procedures needed to analyze Trusses.  You should watch them and then do a lot of practice problem on using these techniques.

Truss Analysis: Method of Joints


#1: Force Acts in same direction as the member, meaning members are only in compression or tension

#2: Equilibrium applies everywhere

#3: Forces can be split into components.

Tricks of Trade:

1. The easiest joints to analyze are those at which all forces and members are either horizontal or vertical.

2.  Start analysis at a node where there is only one unknown.

Truss Analysis: Method of Sections