If you do have not have a strong desire

If you do have not have an irresistible desire, its absence shows that you are new to the work, but you can start to get ready for it in this life. You can create want by thought ; you can't create want by need. Out of the need nature, the training of the need nature can't come.What is it in us that calls out desire? Look into your own mind, and you will find that memory and imagination are the 2 things that bring back need most strongly.
Thus thought is the means whereby all of the changes in want can be brought about. thought imagination, is the only creative power in you, and by imagination your powers are going to be unfolded.

The more that you think about a fascinating object, the stronger becomes the need for it. Then think about Yoga as fascinating, if you wish to wish Yoga. Consider the results of Yoga and what it suggests for the world when you have become a yogi, and you can find your wish becoming stronger and stronger. For it is just by thought that you can manage wish. You can do nothing with it on it's own. You would like the thing, or you don't desire it, and in the limits of the need nature you are helpless in its grasp.

As just related, you can't change want by want. You should go into another area of your being, the area of thought and by thought you can make yourself want or not need, precisely as you like, if only you may use the right means, and those means, of course, are reasonably straightforward. Why is it you need to possess a thing? As you think it'll make you happier. But suppose you know by past experience that in time it doesn't make you happier, but brings you sorrow, difficulty, trouble. You have at once, prepared to your hands, the way to lose that need. Think about the final results.

Let your mind dwell fastidiously on all the unpleasant things. Jump over the momentary pleasure, and fix your thought continuously on the agony which follows the gratification of that wish. And when you have done that for a month or so, the sight of those objects of want will repel you. You'll have associated it in your mind with suffering, and will recoil from it instinctively. You won't desire it. You have changed the need, and have changed it by your power of imagination. There's no better way of destroying a vice than by purposely picturing the final results of its indulgence. Convince a young man who is inclined to be profligate to keep in his mind the image of an old profligate ; show him the profligate worn out, needing without the power to gratify ; and if you can make him think in that way, unconsciously he is going to begin to shrink from that which before attracted him ; the hideousness of the results scares away the person from adhering to the object of need.

And the wannabe yogi has to use his thought to mark out the needs he'll permit, and the needs that he is driven to slay.