Most of LB is 'mainstream' fashion, and it hasn't really been taken up by other styles' communities, but there are lolitas to be found if you look in the right places. My favourite style is classic, be it gothic or casual or any other flavour.
Sometimes lolita can look very over the top, but it doesn't have to be that way - there are more subtle methods of incorporating lolita into your wardrobe if you want to try it out.
Put a petticoat under a full dress or skirt for that elegant A-line silhouette. If you are having trouble finding a petticoat, you may be able to nab one from the children's section, picking the largest size you can find. I got mine from Matalan's kids' section. It's a horrible bright pink and it's a bit on the short side, but it's floofy enough and does its job.
Accessorise with bows, ribbons, lace and frills. Large hair bows and frilly socks are in fashion now anyway and work with all sorts of styles, so you could use them to put a lolita twist on your outfit. If you can't find anything in the shops, it's so easy to just tie a ribbon in your hair, sew some lace trim onto some socks, or make your own lace choker.
Break out the Mary Jane shoes. Their defining feature, the strap, is more associated with little girls at primary school, but with a heel or even a platform, Mary Janes are absolutely wearable by adults. I especially like the lace-up kind.