What are two common strategies that interest groups used to shape public policy

The answer is influencing opinion and forming political action committees (PACs)

Interest groups utilizes different tactics to influence elections and to find candidates that follow their interests.

One of that way can be to donate money to political candidates tat support their positions.

Moreover we have to say that with a really coordinated campaign that uses many different tactics can lead to a good voting results. Infact lobbyists, for instance, use a number of tactics like persuasion, information economic influence or legal actions to convince for example an official that can speak to another one obtaining members. This is a very attractive profession for retiring members.