Radio Shack offers a very useful antenna kit for shortwave listeners.
Otherwise, buy 100 feet of hookup wire and rig it East-West and end-feed it
to your receiver via any tuners, preamps , matchers or preseleectors and you
should be alright. It won't hurt anything if you can only hang 50 to 75
feet, and if you don't have any of the aforementioned equipment, don't sweat
it .

The higher you can get it, the better. If it slants down, that is beneficial
for reducing noise.

If you find your receiver is over loading, reduce the length of the antenna.
Be sure your receiver is connected to a good ground as that improves
reception.

Reception has been poor recently. No amount of wire is going to improve
that, except to say, that a longer length of wire will receive more energy.
Some of that energy is going to be flourescent lights, power lines etc., so
keep that in mind.

I don't know where you are located geographically, but just go with the
flow. I got up at 1:30 AM PDT this morning and heard Australia from 2.310
pretty well, but other frequencies varied - I heard several Ecuadoreans and
Papua New Guinea, but the BBC Relay broadcast from Solomon Islands was
marred by interference from something I could not identify, and other
australian stations from Tennant Creek and Katherine did not fare so well,
but Papua New Guinea from Port Moresby did fine; I heard WLO very clearly as
well, giving weather synopses. It is all a gift, so enjoy what you can hear
S.