I don't have the time.... I don't have the glassware.... I don't have the flair....
There are many, many reasons (or rationalizations) why the would-be-but-won't hostess hesitates to throw a party. But there is one reality that trumps them all: Talk yourself out of entertaining at home, and you will deny yourself one of life's great pleasures—and deny your friends one of life's great compliments. The pleasure, like the pleasure of making anything from scratch, is that of something of unique, imperfect charm. And the compliment is that of literally welcoming people into your space, letting people in.
You don't need money, a mansion, or an inner Martha to have a great gathering. You need friends and/or prospective friends. You need some sort of home; the cramped, cluttered, dog-hairy sort of home is perfectly fine. And you need a concept. Not a concept as in an all-girl luau or Christmas in July (although I keep meaning to do that...), but as in an idea that acknowledges any shortcomings you may be dealing with and turns them into selling points.
Take it from me, someone with absolutely no decorating, cleaning, or (until very recently) cooking skills of any kind: These are four parties that anyone can throw.
Party #1: Random Right-Now Cocktails