any tips to improve my bluff technic ?

I am playing no limit draw poker and holdem on private houses.Game is played max 6 players always same players.
The ante start with 5 Euro but fastly increase to 10 E till 20 even 40 E( buy-in 500 E for draw poker- holdem 20/40 E). Sometimes we make it blind. The game is loose and agressiv. As we know each others tells players for playng years together how can i do to make it more difficult for other player to read me, specially when i am bluffing. I have a tight image which allow me to steal blinds or reraise bluffers but 40 % of my big bluff are discover by 2 players who read me well on this occasion, probably coz of my emotions controlor others tells.

Sorry for my poor english , any tips on this subject will be appreciate.
Thanks