The right time to buy and the right time to sell, it is one of those many factors that you need to consider, there are trading sessions that you may win your position while there are also situation where you might lose your money, keep on learning and in every chance that you need to adjust better to work on it to avoid losing more but instead with your past experienced you might anticipate where the market is heading and you may have that chance to position.
Just keep in mind that trading is a never ending cycle that you need to consider while analyzing each position that you'll going to take.
The trick is to learn from your losses, that's what most newbies do not do. If you can learn why you made a loss, and try to find the mistake you did, and try to avoid doing that again, your results will be a lot better and that is what most people should aim to achieve.
Unfortunately most people just think "oh the market went down after I bought, I am unlucky" and move on, that is not the case, you bought before it moved down, but it would have moved down even if you didn't buy, meaning you bought at the wrong time, try to figure out why you did that and that's when you will do much better on long term. I can tell you that a lot of people who became great traders eventually started out by learning from their own mistakes.