If you were to climb up a ladder, you would look for the next highest rung on the ladder as you step up the ladder from one rung to another. Manifesting works in a similar manner. As you compare two specific desires you have created, you can tell which desires are higher up the ladder than the rest by observing the way they make you feel.
The better a desire makes you feel, the higher up the ladder that specific desire rests. By comparing the various desires you have accumulated, you can tell which rungs you should be using to take yourself higher up the ladder. The best feeling desires you have developed are the highest rungs on the ladder of which you are aware and as you compare one desire to another, you can tell which rung will take you higher up the ladder by analyzing the way they make you feel.