The biggest nail trend I have been seeing for 2015 is having partially bare nails topped with a clear top coat, or opting for a nude color polish.
A continuing nail trend is the moon manicure matched with the bare nail trend.
Layers of Gold
Nails painted gold and top with more gold be it glitter, chains, etc.
Nails painted in one color with a different colored horizontal strip running 1/3 from tip of the nail or even multiple lines on half of the nail. Or go a bit geo with several lines creating a geometric shape on the nail.
Neutral relating colors done in gradient fashion.
From Pale Mint to Pastel Orange, these shades are often seen on a Moonicure.
Instead of the normal french manicure do one reserved making only your cuticle line a different shade from the nails base color. Or go with the traditional french manicure but opt for a bold base color, or add a pop of color on-top the tip as well.
Naturally looking nails with odd ball polish shapes to go against traditional nails.
Add a little interest to nails by just adding a few simple dots.
Tack on some pearls to jazz up any polished nails.