Trill means:

Trill means:hammer-on,pull-off again and again..like Iron maiden solos...Like the trooper solo...Dave murrey solo.Well is it something which is gonna help me?I'm waiting for your reply!

You need to work on the hammering part, which seemed the hardest to me when I learned it just think of your finger as a small hammer. Then, for the pulling off, you need to pull the string downward and release it.

Yes the trooper solo has a lot of trills in it, as well as a lot of other metal solos. Just think Randy Rhoads, Murray, Angus Young, Hendrix... It is helpful to learn any technique possible in the guitar, incluiding trills. Is it going to help you? Well yes, it will help develop strenght and dexterity in your fingers and it will help you run on scales with hammer on's and pulloff's with greater speed on other solos.