I think trends can vary very much from place-to-place and perhaps country-to-country. I do a lot charity knitting for various auctions/bazaars and have noticed how things change.
Have found large afghans do not sell well - people just won't spend the money. However a very pretty, neutral color, or sports team color (if a big local following) can make an excellent raffle item.
Right now I think fingerless gloves/mittens for texting are popular. Also the kind with a flap to convert to a mitten.
Scarves/cowls - find the more delicate cowls do better than the super heavy; possibly to wear as a fashion item rather than outdoor warmth.
Dishcloths/washcloths especially with a bar of soap tied with a nice ribbon or trim.
Similar to afghans but more trendy - mermaid blankets for babies through adult. There is also now a shark version for boys.
I still think the old standbys like hats, scarves, headbands, etc. sell well. Fortunately have some people who are very talented doing the setups even though they don't knit or crochet; display can make a huge difference. Example that comes to mind Christmas ornaments on a tree, not just grouped on a table. Old boot, stuffed with newspaper does wonders for boot toppers; just display one on the boot and lay the others around; then people get the idea better. Have seen small bottles of dish soap and bars of soap in a dish pan - sign said one free with purchase of dishcloth. I am sure you get my idea - think marketing - visit local gift shops and see what they do.