Before You Begin: Be Careful This is a rather simple spell, but you are "playing with fire" before bedtime.

Sprinkle some Jasmine on your pillow, and make sure you have a dream-journal or the like at your bedside to record your dreams in, and brew a cup of mugwort tea.

(NOTE: mugwort is unhealthy in large doses, so go easy, and consult an Herbal Reference book if you're worried.)

Light blue candles on your altar.

If you want to gain insight into your passions or your loves, burn Damiana as well.

Watch the smoke as it coils, and allow it to carry you off into the trance-like state that you spend most of the day avoiding. Say whatever comes to mind, appealing to the goddess or god of your choice to guide your dreams.
Something along these lines:

Blessed be the Lord and Lady, For they created the world, The earth to hold,
The sun to warm, The moon to guide, The spirit to dream.

Take sips of the mugwort tea as you repeat the words, gaze into the smoke,
and when you feel yourself just about to "cross the line" blow out the candle(s) and say:
"So mote it be."

Make sure you have extinguished all burning things before you cross into slumber.

Go to sleep. Dream away. Just remember, you don't always get to hear what you'd like.