Good lighting can make or break an apartment just as much as a dinner date—everything looks better under the golden glow of candle flames. But rather than filling your apartment with tea lights, or undergoing a major overhaul that your landlord might not like, consider the third option: custom lampshades.
Whether you've picked up a bland (but well-priced) piece from Ikea or have a vintage item that's long since lost its accompanying shell, writes the Wall Street Journal, getting a custom shade made for a lamp is easier and more affordable than you might think. (A quick search reveals at least one all-lampshades-everything purveyor in NYC—Just Shades, on Spring Street—that readily offers custom jobs).
Some things to keep in mind before you take the plunge... Shades generally come in two varieties: the cheaper, more straightforward hardback, or soft styles where fabric is fitted around a more elaborate internal skeleton. Options for shape abound (tapered rounds, bells, ovals, etc.) and generally speaking, you can pick your own fabric or one from your lampmaker. (In this way, the process isn't dissimilar from getting something upholstered.)
It's a wise idea to bring your base in to get an idea of what will work, but from there, barring anything that'll look totally out of place in your apartment, you can go pretty wild with patterns. (And if you'd rather not go that wild, simple prints or floral/nature themes are safe bets.) The best part: you get to take the whole thing with you next time you move.