Set the mood

Dimming the lights, lighting some candles and putting on some down-tempo jazz are generally enough to create a chic, festive mood. For an extra touch, buy a mixed floral bouquet from the market, break it up, and arrange the flowers in small groups throughout your party space.

Make yourself at home

A tip my mother gave me a long time ago is to dust off your surfaces with a nice smelling cleaner (such as one from Renovation Hardware or Method) prior to your guests' arrival. Even if you don't clean anything else, your guests will think your entire apartment/house is clean.

Consider this: Guests usually aren't as accustomed to the exotic smells of lemongrass or grapefruit cleaner as they are to Lysol or Clorox, so they wont immediately think, "Oh, she went out of her way!" The impression is that entertaining is effortless for you in your wonderfully clean house.

Decorations

If you're hosting a tea party, your decorations are the cake stands and china. A Halloween party requires a trip to the party store. For a thrown-together party, decorate with items you already have, placing them strategically where guests are likely to notice your decor. Candles are the easiest to use and the most effective.

Important tip: Put a candle in your bathroom. It is the one place in your house that almost all of your guests will visit and where you have a captive audience for your decorations.

Another good place to show your party's theme is the bar. Turn a lei into a garland and drape it across the front of your bar/sideboard. Honestly, I have used tissue saved from shopping bags to make cute red and pink "flowers" when I had people over for Valentine's Day. I took the fuzzy dice from my car and hung them from my chandelier for a games night. You don't have to spend a lot of money to make your home look great for your guests. It's all in your imagination!