Take a look at my answer in this question. I believe you'll find it helpful :)

First, you have to have the absolute confidence that you are really attracted to the qualities of the person, not the person itself. Shut down your emotions and use only the rational mind. If you are emotionally linked to this person, using that person as a model will only hurt you.

When you have the confidence, analyze the person and make notes. Here is how I do it. I divide the paper sheet into 3 columns.

The column to the left is most important. There I write about things like "we have similar interests", "she's interested in spirituality", "she is open minded" and so on. Those thing are rather a matter of choice than of the character. You may argue about this, but it is not that important.

The middle column is character. Second in importance. There I write "joyful", "calm", "compassionate" etc.

The third column, to the right, is physical appearance. It is important, but the two preceding columns are more imporant. I don't want to say that looks doesn't matter etc, because they do.

So after you make the list basing on the person you like, forget about him completely and focus on your list. Make sure there's no emotional connection. You said you have a crush on that person, so I must say again that this is very important!

I almost forgot about the point! When you finish the list, try to imagine the person in your mind. Seeing all those qualities at once is impossible, and that is why you should go slow. First imagine one character trait. When you have this, add another one. For example, I would imagine my soulmate with a smile, laughing. After that, I would add compassion - I would see her helping a homeless or a sick person. After that, I would link those two qualities in one image. After that I would add another qualities. Or I would make many short films about her in my mind. When imagining the appearance, I wouldn't be too specific. Of course, I could imagine the long hair, but seeing a concrete face would be just too difficult.

Oh, and the image doesn't have to be specific. You just make a symbol that will guide "the universe" to get you someone as close to your wish as possible. You can see a metaphor, symbol and do not worry if the image is blurry. Do not worry if there is no face. You are not creating a new life right? You are just attracting a man that already exists.

If you still experience difficulties, it could be that your problem lies not in manifestation, but in unreciprocated love. If that's the case, then I can especially relate to your situation. I am in the same position right now, feeling really helpless.

There's an mportant issue to be addressed with attempts to manifest anything: desire.

There are several schools of thought relative to the issue of the "origins" of our desires, the two most prominent being that they 1) the animating force behind our lives imnplanted in us when God--or whatever you believe "first cause" to be--incarnated part of itself in us, and 2) We are the creators of our own desire as the capacity for desire is in the very tissue of our being and they lead us through life like a compass to find those people, things, and experience we need to fulfill the destiny which we chose of our own free will. In either case, one must consider his or her desires sacrosanct and not attempt to understand them with the mind's go to tool, reason.

Desire--or for that matter any intense emotion--cannot be approached by the intellect like,let's say, a mathematical problem: we can see representations of desire--images--in our mind or use words to attempt to describe it but the thing itself is not comprehensible to thought.

Jaianniah ( a very pretty name) you feel desire for this man. The "Universe" will not punish you in any way for feeling such a thing. We do not have control over such a feeling any more than we do when we feel inspired by a beautiful painting or great poem.

If you were in a museum and saw a Monet or Picasso that was the property of the museum, you would still desire to own it if you found the work captivating. Now, of course, such artwork is beyond the ability of most of us to own but you would not chastise yourself for falling under its spell or being attracted to its beauty. As a decent person, you would not plot to steal it. If drawn to is with sufficient emotion you might find a picture of it and imagine what it would be like to have a very, very good reproduction of one that could elicit in you an analogue of the feeling of the original.

If there is a potential liability to "putting a face" on the man that you intuitively feel to be your ideal, it's that you risk limiting the "Univerese's" infinite possibilities. Like all humans, your experiences are limited. There are approximately 3,000,000,000 males on the planet. Let's assume only 1:1,000,000 would have the psychological and physical qualities you find desirous in a man. That still leaves 3,000 men who you, in theory, MIGHT desire, perhaps as much ormoreas this man.

This lack of experience is not to be dismissed. We must always remember that the Universe would not be so indifferent or cruel to limit us to a "one and only". What would become of us should that person die at a young age?

We have an infinite capacity to love and to desire in a world that has provided us with more potential opportunities to fulfill those desires if we lived a thousand lifetimes.

If you wish, you can without fear of losing anything, use the image of this man like you would the initial draft of an architect who will collaborate with you on the design of your dream home. The "Master Builder" can and will, if you do not limit him, say to you, "Ah, yes, it is equisite, but might I suggest a way to make it even more beautiful than you would have thought possible?"

All that you in your childish dreams have fancied as lost, I have saved for you at home"
~Francis Thomkins, "The Hound of Heaven"

I have been trying to manifest my soul mate through visualization, but the thing is that I can't visualize without having a specific person in my mind.

One important and perhaps the most difficult part of manifestation is letting go. Detaching from your desires raises you to a well-balanced, non-judgemental energetic level where "things become possible".

"Visualizing a person" often includes focus on external qualities as well as internal. In a soul-mate, you are looking for higher qualities, no matter what that person looks like, has got, does, is interested in. If in this case visualising means for you "being stuck" with the image of a certain person, stop visualising, stop imagining. Find the essence of who your soul-mate is, and accept that in this life you may not meet your soul-mate. Let go completely and truly, without any expectations, and don't look back.

By the way, I'm speaking from experience: Seven years ago I came to the decision to remain single, simply because the combination of what I was looking for in a partner was nowhere to be found, and I wouldn't do with less. I accepted this for a fact and genuinely let go of the idea of finding who I wanted, that is I stopped looking. The essence of my soul-mate was (and is) joy, playfulness, and kindness - any other characteristics I would be able to accept. After this decision, after I let go of the last hope of ever meeting such a person, it was 27 hours until I met him. (In fact it was someone I knew superficially.) What still surprises me is that apart from having the essential qualities, he looks exactly like the person I want to be with - although I would never ever have visualized him as he is :-)

If you focus on a specific person, then the universe cannot bring you who you really need. Instead of focusing on that person, focus on the feeling you have about him instead and put a question mark over his face.

If we get in mind that we want a certain person, who is either not available to us or who is not right for us in some way, then we will keep our real soulmate at a distance. Believe me, I did that and wasted 3.5 years of my life.