One of the most important things, right off the bat... Make sure you listen to their requests and needs. Your customers will be the ones thanking you if you go above and beyond their expectations. They usually seem to like private freebies, gifts, like products you need reviewed, or exclusive sneak peaks before release... etc.. Discounts on future orders... Birthday wishes are always good... Personalize, personalize, personalize. Can't stress that enough. The more of a personal connection you make with your customers, the more comfortable they feel. If they can feel like they can call you with a silly question and get a quick honest answer, without being condescending they will keep coming back...
I always give discount for my loyal customer at the end of month and give them some tips on how to make their site more popular
I send fruit baskets to my customers (they love them!).. the company I use is EdibleArrangements ... they deliver fruit baskets anywhere in the US & Canada...
depends on who you are customers are... Any discounts for future purchases work great for every business though
Good customer support. Solve their problems and issues quickly and promptly. Thank you cards are useless. Better give something of direct value to customers like discounts or freebies.