You are most likely to have a dream vision when you are comfortable and relaxed. It is best to do this type of work before you sleep at night. Perhaps meditate with the intention of working with your spirit guide before laying down to sleep.
You'll start out on a path somewhere (I started on a paved road) and that path will eventually take you to a field. In that field you should see an animal, if you get there before the animal does then wait for it. Do not run away, if you do then you may never have the dream again. The first animal you see in the field should be your Spirit Guide, but the animal may lead you away from the field before he/she lets you see him/her clearly.
This type of dream may be induced by request. Simply ask your Spirit Guides very politely to send it to you and make sure you are very relaxed and clear minded when you go to sleep. I would suggest drinking some tea and meditating to help get you in the proper state.