To echo Evo ...
Essential in this business to gain a visual view of what the situation is. I.e. the wind is going to come from the vector mean (i.e. in between) the two wind vectors you're given.
But, always try to visualize what is going on - you'll build situational awareness, which is vital when you are flying in busy airspace (dealing with other traffic, wind, where you want to go, and how you must get there.)