according to research by J. Allan Hobson 95% of our dream is lost within the first minute, the second you awaken you should immediately write down what you remember. get a tape recorder if you feel it would be easier [same with a sketchbook i had an old art teacher/witch who would sketch her dreams.] it is also estimated that we dream 5 times in a night because we go through cycles of R.E.M. and non-R.E.M. over the 8 hour span of sleep. it's in stage 4 of these cycles where we dream. some people have trained themselves to wake up after stage 4 to write down each dream. [this can also explain why you might have a random dream where you're running through a forest and suddenly are flying, you've unknowingly slipped into another dream]
different foods, smells, and temperature can effect your dreams as well. heavy foods before bed such as cheese can trigger nightmares [i have horrible nightmares if i eat dairy before bed. oddly enough my friend who volunteered in my sleep study back in college was effected differently, cheese makes her have very vivid dreams.] try experimenting with foods before bed. smells such as peppermint can aid in dream memory. i don't know if a fan would help or hinder you though, wind on a persons face who isn't use to to it can effect their dreams. i sleep with a fan so it's no big deal for me.
be sure to keep a journal by your bedside and record everything, the date, and what you've done before bed [meditation, glass of warm milk, made a lavender pillow] then the second you wake up, before you do anything [don't lie their for a minute either] grab the journal and write/sketch anything you remember. even if it's just 'ball bounced down some stairs'. slowly you will begin to remember more.