To prevent major losses need to ptetrack on the day of play.
For vb , take 80 spins data per direction. Look if variables in qwestion do have desired frequency. If you attack drop points, they have to correspond to the bulk of your data. If they not- do not play.
For ds, look how often variables repeat, if dealer start to throw different spins one ofter other ( unless you can recognise type of spin) stop, colect the data.
There gonna be periods of consistency and periods of " whatever". Avoid " whatever" in your play session.
Set up your target situations in home, there is no time to make deep data analysis in casino. Situation will correspond to your target one or not, if it doesn't, do not play- collect data.
In general, these who want to be a player , not gamiler, need to adapt resercher mindset. If you follow a roulette wheel , it's for studing purposes only. You bet only when you recognise situation as " understandable", " familiar ", " studied previosly". Attack whatever you attack on its prime. If situation stops to be good, stop betting or adjust.
About adjustment. Be careful, sometimes it's a very bad idea to adjust vb offset based on short term data. Unless you are familiar with the wheel and what it does, skip play when adjustment is required. Only adjust for a changes that you profiled earlier based on previous data taken. Many novice players do jump into the game very early and start to adjust whatever.... it' normally is deprimental to their bankrolls. Ball will beat different places and with different timings, will have a different jump..... doesn't matter, as long as it fits your model made in home ( based on previous days), follow your model. If it doesn't fit the model, collect data, do not bet.
Following this simple guidelines will permit you to structure your betting proprely and avoid main part of what others call " random fluctuations". You do not belive in santa clause , right? Why would you belive in random fluctuations?
Random in this case just mean that situation do not fit your model. If it doesn't, you are in terra incognita, behave accordingly, collect a data for future studies..... who knows if you find something worth your attention there? Instead of gambling...research