Just the inhalation of lavender will help a headache related to stress especially. It can induce you to a peaceful sleep by just having a sachet under your pillow or spraying your pillowcase with lavender linen spray. Lavender oil can be used externally to soothe aches and pains by rubbing some oil on the area affected.
Beauty wise, it can be used for acne flare ups and as a balm for sunburn just by mixing a few drops to a little water and then rubbing it on the affected area as well. You can rub the oil undiluted onto insect bites and stings. Also...I know, but wait! Lavender can help repair damaged hair too!
If you want to dry lavender, collect it when the flowers start to fade...at the end stage of flowering and hang upside down in a cool place, in a paper bag. This way when the flowers fall off, you can collect them!