On the one side, you must be silent and passive, or 'receptive' to perceive and touch the stuff you intend to work with.
On the other, you exert will and intent to make it do stuff.
It's kind of a yin and yang (figuratively speaking) to juggle both at once. You might imagine that with one hand you receive and sense, with the other you put out force. Hold the nail, hammer the nail.
Will is the leverage of force which you bring to bear, the size and speed of your hammer. It's useful to magnify will (by any of a wide range of approaches) so as to be able to put more 'oomf' into your intent.
Will is affected by your consciousness. The extent to which you truly know yourself, and master the whole of your mind (a process more of exploration than conquest), will greatly affect how effectual your will can be. For example, going on a diet is hard, because part of you doesn't want it. Succeeding is hard if part of you is afraid to succeed. etc. Get as much of the varied myriad facets of your psyche uniform in intent & purpose and resolve, and you'll see a huge difference in how much 'oomf' you can bring to bear. This exploration of the great deep 'within' could warrant volumes of further discussion, but that's the basic idea of it as it relates to energy work.
Bringing a very strong 'oomf' to bear can FEEL contrary to being sensitive and receptive ...but it is not a contradiction. It's a dance of coexisting opposites which need NOT be viewed as canceling each other out.
I think that's the main underlying basics which most books fail miserably to explain. The actual techniques you might (or might not) try to use, are easy to find in any book on the topic.