Hi mate, a good way to start out is if u find a patch u like, ie: the love of god preset u mentioned....then tweak it until you have the desired effect.
Or, find a song that u like that has the sustain that u are after, and try and match it with your preset, as in, play something on your guitar, press play on the cd to see how close you are to that sound, pause and tweak...repeat until insane or until u have the sound u are after....\
It will be dependant on what guitar and pickups you have....so, what guitar and pickups are u using?
Thanks for your reply JaxN4.
I'm using Ibanez ARZ800 with EMGs. I thought it was something about the guitar too, because I found some presets rated by many as "really good" and "close to original sound", yet I wasn't satisfied with the sustain, especially when bending frets near the bridge...