It took me three days, at first my lucid dreams were lasting about 30 seconds each. Then as I focused more on it and did reality checks on a regular basis. Now my lucids average about 20-30 minutes each. You just have to believe in yourself.

Surprisingly, I don't really use any techniques, I just think about LDing all day and will usually remember I was thinking about it during a dream (I guess this is kinda a technique)