Roulette has been in casinos for over two centuries and online for thirty years. The rules have not changed. What has changed is the speed and accessibility at crypto casinos, where you can play provably fair RNG roulette or live dealer tables with crypto and withdraw winnings within the hour.
European vs American vs French roulette
The single most important decision in roulette is which variant to play. European roulette has one zero (0), giving it a house edge of 2.7 percent. American roulette has two zeros (0 and 00), which nearly doubles the edge to 5.26 percent. There is no reason to play American roulette over European when both are available.
French roulette has the same single zero as European, but adds the La Partage rule: if the ball lands on zero, you get half your even-money bets back. This halves the effective house edge on those bets to 1.35 percent, making it the best roulette variant available. When French roulette is on offer, take it.
Understanding bet types and house edge
Every bet in European roulette has the same 2.7 percent house edge. Straight up bets on single numbers, red/black, odd/even, columns, dozens, the edge is mathematically identical across all of them. This means there is no bet that is statistically better than another in terms of expected return.
What differs is variance. Straight up bets (35:1 payout) produce rare big wins and frequent losses. Even-money bets (red/black, 1:1 payout) produce frequent near-break-even sessions. The choice is about how much variance you want, not about finding a better edge.
Betting systems: what works and what does not
The Martingale (double after each loss) is popular in roulette because even-money bets seem safe for it. The problem is that a losing streak of 7 or 8 rounds turns a 1-unit base bet into a 128-unit or 256-unit bet. Table limits exist specifically to prevent the strategy from working indefinitely. The Martingale does not overcome the house edge.
The most honest approach to roulette is to decide your session bankroll, set a target for when you will walk away up, and pick a bet size that gives you at least 50 rounds before you hit zero. Beyond that, the house edge is what it is.