How to increase your friend list?

Hi,

I have seen many people talk about their facebook accounts with 5k members in their friend list and people are managing 5-10 accounts with same numbers.
I am curious to know how they manage to increase their friend list to that number? Are they that free to sit all day and add them manually? I am sure they are not, so whats the trick they using that they get to increase their list?

Can any share their tips and tricks with me? I am trying to achieve those numbers and trying hard but with no luck so far.

Thanks in Advance.

I have had a few accounts where I have rejected over 300 friend requests on each account, have to be quality friends, not fake account friends.