You can't totally have a no-risk game. Risk is what gambling is. It's what makes it fun. If it didn't have a risk factor, then it would just be giving away money. And no risk is no fun. People would only do it if they were greedy.
There are many ways to stay safe, though. If you have a huge bankroll, you can try a martingale strategy. Or if you want, follow your instinct. For instance if it's a dice site on 50%, and the previous 5 have been "LO"s, then bet a "HI".
Martingale is the safest way to lose your pot imho. Either way you turn it around, in the end you are bound to hit a loosing streak, and due to the nature of martingale,
you will once start losing until you go bust. Every new roll at 50% is nothing more than 50% chance, and all statistics of previous rolls is just a distraction, don't fool yourself.
The only example where i would use martingale would be in sports betting. Choose a team and from season start betting that they will win/lose, there's 99.9 chance you will win ?!