Normally, trading itself is not even something you should always expect 100% win, strategy is just there to guide you. I know so many people who have made the mistake of thinking that once they have the knowledge and strategy, they are already set for big wins, but it is trading, and you are only taking advantage of possible fluctuations, so you really want to put in mind that losses are also possible, but how you are able to manage them is what would determine how good you tend to do eventually.
True! I tend to think sometimes, a lot of people always never get to know that beforehand that losing is also part of trading and that is why you need to know that to be able to know how you can always manage the reward and the risk anytime you are trying to make a trade.
Like you said, with strategy, and TA, they are more or less like a guide to anticipate what the market is possibly going to bring, set a trade for yourself based on some price action and your strategy, and then know what you are looking at when it comes to setting stop loss, where you are picking your profit and where you are getting in.