Hey, forgive another noob question, but here goes...

I've been reading here that sustain is affected mostly by the type of wood of your guitar. I've got a Samick acoustic (SW 015DB) that I can't find any information on, so I don't know what kind of wood it is...anyway, I can't get much sustain at all, and I'm wondering if there's something with my tecnique. I'm fretting as normal, but can't get a note to ringfor more than a second or two. Another thing I've heard is maybe lowering the action?
This affects me mostly when I try hammer ons and pull offs. I know an acoustic isn't ideal for this, but I'm sure I can do better than I am now. When I strike a note, then 'hammer on' the next fret, the sound dissapears almost immediately...same as with a pull off. Am I doing somehting wrong, or is this just my guitar? (I got it from my dad, who got it from us as a gift years ago before I knew anything about guitar...so I just got a cheap one from Cash COnverters. Can't imagine it's a very good one...)

Thanks for the help!
"He has a woman's name and wears makeup. How original."
--Alice Cooper, on Marilyn Manson.
^ Maybe...remember, a lot of cheap guitars are essentially plywood with a wood grain or finish painted on.

Partscaster/Tele into a bunch of pedals, a Maz 18 head, and a Z Best cab.
Sorry, can't get a pic...my digital camera is toast. I'll see what I can do soon, though.

But seeing as nobody said anything about my tecnique (or lack thereof!) can I assume it's just a cheapo guitar? I'd like to replace it eventually, but it plays well enough for now...except for this sustain.

Info I can give you: it's a solid black finish, the soundhole has white rings around it, and it's trimmed in white on the edges. The fretboard is black, but it's obviously painted because it's wearing in places; the real wood looks to be a dark brownish colour. Looking in the soundhole, I can see an edge of the top that's not coevered or painted, and it almost looks like thin particle board. Don't know if that's any help...not entirely sure what I'm looking for...
"He has a woman's name and wears makeup. How original."
--Alice Cooper, on Marilyn Manson.