Say I have a sheet music with the right hand melody and just plain chords for the left hand. Is there any specific technique or anything pattern to improvise?

umm
arpeggios(or however you spell it), add in a few trills, change up the rhythm a bit...try those perhaps <__<

Before you do any improvisational pieces, you need to take a lot of theory and know it well. Pulling crap out is useless and most likely really bad sounding if you don't know at least some related scales and I-IV-V stuff, and thats just real basic.

The most simple thing you can do is change the rhythm. Then you can start adding frilly things like arpeggios, trills, grace notes when you get good.

Just have fun with it all is how I started. The best thing for improving (or also known as comping) is to "hear variables" of the melody and rhythms then make them happen.

Otherwise if you want to just improvise (from scratch mainly) that's a whole different story.

Say I have a sheet music with the right hand melody and just plain chords for the left hand. Is there any specific technique or anything pattern to improvise?

If you have the chords, then with some knowledge of theory and piano skill, you should be able to decorate it easily, like some of the suggestions posted here.

What I want to say though, is to not overuse arpeggios....the sound of a melody over a repeating arpeggio pattern becomes very repetitive after a while....

Thanks guys :lol: