Im sorta new to the whole tanking gear i tried to do some research on this but having a hard time understanding it, as for as i know there are three things i need to focus which are Defense rating, shield rating, as well as Absorbing rating (well there's others like endurance, strength etc.) im really confused as in what should i really focus the DF,SR,AR, i was told DF is the most important then comes SR so is there a % i should aim at per category please help

in the early stages of the game (pre-50) it should not matter too much. Just use whatever reasonably suitable gear you chance upon. Approaching endgame (50-55), go mainly for shield and absorb. seems to work better then defence now imo. my shield and absorb is about 35% now, aiming to get it to at least 40 or so. High defence suffers now. just my 2 cents

And don't listen to people who type stuff like that which is just stuff apparently based on guessing

 

Go look at the actual optimal stat distributions based on mathematical analysis

 

http://www.swtor.com/community/showthread.php?t=616779

 

http://www.swtor.com/community/showthread.php?t=567164

For my sith juggernaut I just got ahold of a custom shield generator and all custom armor full of the highest guardian mods that my level is allowed. Then I'm placing all my skill points in the immortal tree (not sure what it's called for the Jedi). Anyways, whenever I max out my planetary comms, I go upgrade the mods in all my armor, shield generator and saber. Playing flashpoints, I find that I'm quite indestructible, even with a bad healer. I think you don't really need to worry about the exact stats til endgame. For all the lower level stuff, just having fully up to date gear is more than enough. Gotta make sure to have a good DPS companion and keep their gear up to date too, otherwise it takes too long to kill things. With a full tank spec, you don't do a whole lot of damage compared to a DPS class.