Here is a little insight i had about finding the right amount of  effort in your yoga or meditation practice. To be a little more clear  its really all about releasing any conceptual basis for what effort is  all together and finding that place in the middle.
 Now when it comes to yoga and meditation you often come up against a  paradox that does not appear logically possible. Although if you let go  of what you think you may know and allow your self to just experience  you will understand the meaning of the paradox. A frequent teaching is;  “find the place in the middle”, “not too tight, not too loose”,  “effortless effort”, “Stay active but remain relaxed”, “go to your edge  but no farther.” It comes in many different sayings but what do they  mean ?
 Lets consider the concept of effort. Since everything is relative and  a concept only really makes sense in relationship to something, (Yin  and Yang , Positive and Negative) the concept of effort has no meaning  unless there is something to compare it to. Thus we have effort and non  effort, in order to intellectualize this concept we must separate it  into opposites. The amount of effort or non effort you may be  experiencing is a subjective amount. No one else but you really knows  how much you may be or may not be exercising effort. We draw arbitrary  lines for ourselves for what we consider too much effort , not enough  effort or just enough effort. The idea is not to create the concept for  some arbitrary point of “just enough effort”  but it is too let go of  any concept of effort what so ever, with out grasping and with out  aversion.
 Imagine a number line -5 -4 -3 -2 -1 0 1 2 3 4 5. Lets say this is  our effort scale. The positive numbers are effort and the negative  numbers are non effort. At any point you may be able to rate your self  on this arbitrary scale, telling your self how much effort or non effort  you are exerting. When you continue to hold on to this dualistic  concept, on one side effort on the other side non effort, you are in a  constant battle either grasping on to where you think you should be or  avoiding where you think you should not be. How do you find the place in  the middle ? What is in the middle ? That’s right “Zero”. What does  zero mean here ? It is nothing at all or does it have some kind of  quality. In math zero is not simply nothingness it has attributes and  its own nature. In meditation or yoga zero pertains to the concept of  emptiness, a concept not having an intrinsic value with out a relative  nature(Non-dual realization).
 So in order to find “Zero”, the place in the middle, effortless  effort, you must let go of  dualistic concepts such as effort or non  effort. Experience your current state fully allowing your self to be as  you are without intentionally holding back or pushing. It is this  thought, that we need to be at a place other than where we already are,  that places us on the relative scale. When you can dissolve the concept  of effort all together with out falling into the positive or negative  range you will experience the solution to this paradox.
Metta,
Danny