The trick is to do very small bets, so the chances of you losing all your BTC is if you get 14-15 losses in a row.
If you have 0.1 BTC, do 0.000005 or 0.000003 bets. This takes about an hour to get 0.001.
Or, start with 0.00002 to speed things up, but it'll take 12 losses to lose it all, or 11 with 0.0004.
The problem is that it gets very boring because of the slow pace, so people (myself included), bet more here and there because they "feel lucky." I usually bet more after I had 9-10 losses in a row and finally won again. What are the chances of another 10+ losses in a row, right? If you have 0.1 BTC,
DON'T ever start betting with more than 0.0004, unless you "feel lucky," but you'll eventually run out of luck.
I doubled my initial deposit with Martingale multiple times, but then lost it all because I was "feeling lucky." The evil of gambling. Know when to quit.
It would be great if there was a script that did this slow betting for you, which takes a couple of hours, and then stopped once you've doubled (or 50%, whatever) your initial stake (or in rare cases, lost everything, or are 1 bet away from potentially losing everything).
Edit: looks like I've found one:
https://bitcointalksearch.org/topic/seuntjies-dicebot-multi-site-multi-strategy-betting-bot-for-dice-with-charts-307425