Venomancer is a great multi-purpose support hero who, depending on the skill build, can accomplish a large variety of tasks, including ganking, pushing, harassing, counter-pushing, and teamfighting.

Generally you max wards by 7 or 8, build a Mek and Wand, and eventually if you're rich try to pick up an Aghanims Scepter. You can farm these by teamfighting/ganking, or by stacking wards in clumps and pulling neutral camps into them.

Check out YouTube.com/PurgeGamers for videos and tips!