What are the principle strategies that groups use to affect policymaking? which strategy seems to be the most effective, and why? are certain strategies better suited for different types of interest groups?

The two strategies are Iron Triangles and Issue Networks.

The most effective strategy is the iron triangle because it consists of a reciprocal benefit between Congress, bureaucrats of the government, and lobby groups that have particular interests. Each participant performs an action that will benefit the other group, and in this way, they create a permanent and solid bond between the 3.  

Certain strategies are better suited for different types of interest groups:

answer; allows decision to stand;

answer; jewish immigrants;