With summer kind of being in Scotland, fruit patterns are all over the place - nails, fashion, homeware. Watermelon and pineapples are my personal favourites, and I currently have a watermelon clutch from new look (which a friend very nicely got me as part of a graduation present!) and a pineapple backpack from topshop.
I was going to do watermelon nails a few weeks ago bit of course my nails broke and I had to but them down to nubs again :(
Marble swirls are another kind of nail art you can do that looks harder than it actually is (and also a lot less messy than water marble).
All you need to do is blob on your polish and swirl the polishes together (still wet) with a cocktail stick or bobby pin or a dotting tool. Some nails can turn out not as great as other nails (a couple of mines had some bare patches I didn't notice till later) but I think it's nice that not all nails are the same or uniform within themselves!