What are they? How do you know? Who will tell you that you have them? Identify them. Be aware of them. Just like blind spots when you are driving, you should constantly be managing those areas to make sure you don't change lanes and there is a car right next to you.
You have to be doubly aware of the areas you are weakest in order to effectively manage those areas. But, being aware doesn't mean constantly "working" on your blind spots. Spend time working and focused in your areas of strength. Just make sure to check in the mirrors on the left, right and rearview on a regular basis to know what is happening around you.