If you dont have a grounding in musical theory such as keys, scales etc then it can be daunting when starting out...

try sampling a melody off vinyl, loop it in fruity then try to copy the melody using another instrument, this can help you get an idea of what notes work well together and can spur off some ideas of your own...its good to see what that producer was seeing on his sequencer at the time...

also dont forget the huge change a shift in the bassline can make to the melody on top...this is quite a cliched sound now but still gets you in the gut everytime it works...common shifts are 2 semitones down...for example>> note plays offbeat C on first 4 bars, a# next two bars (or g# works even better)

let us know how you get on mate...