You can also modify the priority of each shaker. When you shake the phone in a particular direction, there might be multiple functions that can be invoked. The app will only invoke the function with the highest set priority. You can change the priority of a shaker by pressing on it in the shaker list, then clicking the Change Priority button, and then long pressing on the shaker to either increase or decrease the priority.
If you notice any other useful tips, post them in the comments.