Well, my girlfriend and I played some roulette this last weekend.
It was a while since I dabbled with Roulette, and I had forgotten a lot, and did not recall numbers.
So, I stuck to the basics, and explained my basic thoughts to my girlfriend to complement her knowledge, and she did great.

We started with the basic strategy of Choosing Red or Black, and/or Even or Odd when the situation was right.
Since we were starting with a relatively super small stack of chips (money), we needed to improve the odds in our favor by waiting for the roulette board to have the right pattern.

What is the right pattern?
We waited for the roulette board to display at least four or five numbers of the same type (types equal odd, even, red, or black).  A green number (such as 0, or 00) was considered a Reset, and we started all over on the waiting.  The unfortunate thing about having a small stack is that you will need to wait a lot.  My girlfriend was not too pleased about this and wanted to play, play, play.

Once she warmed up, she began to go outside the basic strategy and zone in on numbers that had not come up in groups shown on the board.

Then I realized that this particular roulette table was getting a green number regularly, and one was due soon.
I suggested playing the middle line zero.  Playing the middle line zero pays 17.5 to one, instead of 35 to one.  Yes, you can play both the 0 and the 00 at the same time by putting your chip/money on the line separating the 0 and 00.

So, she began deciding when to also add an extra chip on either the line separating the zeros, or she placed a chip on both 0 and 00.
After only about 3 bets on the zero line, we won!  That was a sweet win, plus all the other wins she had gotten by betting on groups of 6 numbers or four numbers.  She increased her chips stack (money) by 800% before we left.

I found it interesting that my girlfriends unconscious initial thinking was since red had already came up, then maybe red will come up again.  I expected the opposite of course, based on basic probability.  If something comes up, it is less likely it will come up again in the near future, or immediately after.  I understand both tactics, and they really are opposite of each other.    Once she noticed this unconscious behavior, she changed paths to playing for the opposite.

WARNING, I have seen the whole roulette history board come up all the same color a couple of times (that is like 12 or more of the same type).  So, if you think you can just keep doubling your bet to counter this.... not so quick.  This is why the casino's have limits on how much you can bet.  Because you will reach the maximum limit before the roulette table changes in many cases, and so you end up losing.   This takes us back to improving your odds by making sure several of the same type of numbers have already come up before you bet.  This way, you will not have to double up for as many hands, and have a better chance of catching the change/turn on the numbers.

The minimum bets and maximum bets are selected for a reason by the casino, and that is to prevent strategies like doubling up on the next round every time you lose on the previous round.

Of course once you start considering that the dealer manually rolls the ball at different time intervals and different rates, and waits different periods of time before the ball is released for drop, you begin questioning if the odd, even, red, and black idea really work.

If you think the Casino's do not cheat, then maybe you should watch carefully and be aware just in case.  I am not saying they do, but watching them sometimes makes me have questions.  There are governing bodies that regulate them supposedly to prevent such occurrences.