Don't eat for about 2 hours before going to bed. Heavy meals b4 bedtime mean that your body is still digesting and therefore can't fall into a deep sleep, making you remember dreams and nightmares
As stated avoid any food for two hours, let in a little fresh air, read a boring factual book or mag, "New scientist" does it for me (It concentrates your mind on factual, rather than imaginary horrid thoughts) meditation is worth a try, also lavender under the pillow, or a hop pillow,
Hope this may help. sweet dreams.