I never watched NCIS Los Angeles nor the "Original" NCIS till now. As I heard some pretty good things about this show, I just wanted to know, if I should better watch NCIS first before I watch NCIS LA?

As a long time NCIS fan, and a current NCIS:LA fan, I don't think that it matters if you watch one first. The shows are very different. The only similarity (other than occasional crossovers of characters) is that both deal with crimes in the Navy and Marine Corps. NCIS is more of a standard cop show (ie murder of the week) with a very rich character arc, while NCIS:LA is about a division of the same investigative organization but their investigations tend to involve more undercover projects and live victims.

The problem I could see with starting out on NCIS is that they are now 7 seasons in. The show invests so much into the characters (I'd say more than any other cop show I've seen) that is helps to have the backstory. I watched the first season (I started it from JAG), and then went away for 3 years. When I started watching again, I had to really learn what had happened in the backstories to be able to understand what was going on.

NCIS:LA is still in it's infancy as a show. We are just getting to know the characters and the group dynamic. It is probably a show that is still early enough to start watching and not feel like you've missed too much.

There are some people who LOVE NCIS but can't stand NCIS:LA. and there are others who tolerate NCIS but really enjoy NCIS:LA. I, personally, find both to be highly enjoyable shows. I hope that this gives you some idea!

It might help in some ways. For example, in one episode of NCIS Los Angeles, a main character (Abby Scuito) from the "original" NCIS guest stared on NCIS LA. Watching NCIS might help you know more about that character.

I think you should watch the original NCIS so you'll know more about the show.

It doesnt really matter which one u watch first

Ive been watching 4 bout a year its really good to get the ropes i would watch a few of NCIS then though it deosn't matter

No,definately! U dont need to watch NCIS first cause the characters are different and the series stands on its own. And in my oinion NCIS:LA is a lot better than the original!!