Two Plus Two Older Archives - When to stop bluffing?

Today I probably did my best tournament ever at the Nordic bet freeroll 5000$. Eventhough I didnt get to the money, I felt as this was the best iv played ever. During the tournament I almost allways kept myself a couple of steps above the average stack, and even if it may not seem like something for the lot of you, for me it was a great achievment.

Now, the problem I got myself into several times and the issue that ironically saved me a coupple of times but then eventually ended my progress, was that I didnt know when to stop bluffing. It would for instance start out merely as an attempt to steal the blinds, but then getting called or reraised. Eventhough they called me preflop, on the flop on the turn I would continiously make big bets as to try and buy the pot. It actually worked most of the time something which to me was quite the suprise.

When there were probably about 200 people left (130 places being paid) I was sitting on the button with about 33.000chips. Everyone but the guy next to me folded and I raised to about 5000. Blinds was 500/1000. Everyone folded exept big blind whom had around 60.000. Flop came and I bett somewhere around 8000 and big blind called. Turn came and I bett like 15 thousand, he called, river came and desperat as I was I shove the rest of my stack, he calls and shows pocket fives (!) to my unimproved K10s. Im out.

I actually realize how dumb this might seem as im writing it, but at the time it seemed like a very clever move seeing as I had won a coupple of big pots like that before..

Anyone got some thoughts to what I should try to do? Sitting on top of tips as to how I can improve this somewhat stupid leak?

Any helps appreciated.