There are a lot of things that you can take direct control and do something about. Infact, it will be a good idea to classify all the things you can do something about and those you have no control over.
Once you have done the classification, you may be staring at a long list-"so where do you begin?"
You cannot start working on everything at once.
Use the 80:20 rule.
Only 20% of what is there on the list will give you 80% benefit. Look at the list of what you can do something about and further classify using the 80:20 rule.
Choose 3 items from the 20% list and start working on them.
Your life will change before you even know it.