Finding ones Guardian requires a little research and a few other skills to make the journey more vivid (or should I say lucid) as well as more meaningful and deep.
First off, the research part of this experience: you will need to know where in the Astral Plane your Guardian is. You should already have a small subliminal connection with your Guardian and that connection will make this easier (after all s/he wants to meet you as much as you may want to meet him/her). To find the realm of your Guardian think about the spirituality you find yourself connected to the most and from there the spirit world of this spirituality should contain your Guardian.
Next in the research is the race of your higher; this is also connected to your own spiritual background since every spirituality has its own "angels and demons" though this experience goes beyond Angels and Demons alone.
The next part of this journey is the skills you will need to make the trip safely: Lucid Dreaming (Astral Projection particularly though you would be surprised how close to the Astral Plane you can get with just plain old Lucid Dreaming), Meditation, and vivid Visualization skills. You will first need to meditate (only do not ground yourself since you want to temporarily leave this space and reality for a time rendering grounding counterproductive) and focus the meditation on familiar backgrounds (places that seem to come to you more clearly and easily) and use these for the journey ahead.
Next comes the fun part; go online and browse through images related to the backgrounds you already find yourself connected to (if you happen upon any backgrounds that you find couldn't think of earlier that come to you naturally then don't hesitate to add them to the visual guide in your mind). Next after you have a reasonable idea of the background(s) you will be seeing, you will need to have your own image memorized so you can insert yourself into this world (you'd be surprised how hard it is to remember your own face when you are dreaming) wait until nightfall and this is when the Lucid Dreaming (AP if possible) comes to play.
This incantation is to help your Guardian reveal him or herself to you:
"Please show yourself to me so I can see, please come to me.
So now the world is clear, and now I am here."
You don't have to use, it's just for if you are struggling.
The rest is you, and so I can say no further, if you need a guide through the world of your choosing (one will appear unless your Guardian intends to challenge you.