Note: This question is subjective so the answer might be different based on the person.
The way to make the best decisions in life is by not only reflecting on how the decision affects you, but how it affects others as well. Your actions have the ability to either help or hurt others and its important to think about what might happen in the future based on your decision. I believe a lot of people struggle with this idea and have a hard time imagining it, but try to put yourself in the view of others or ask them yourself whether or not they agree with the decision. Every action can change some aspect of your life, as little as it may be. Its also good to view the pros and cons of bigger decisions and decide if the decision is worth the cost. You may also need to decide if you are able to follow through with the decision, or if the task may be too daunting for you to handle. I don't think there is a decision you can make where there isn't any regrets or "what ifs", but you can still make the decisions that are most beneficial to both you and others.