Marcus said, you can improve in things that you are awful at and be medioka at it or you can improve the thing that you are really good at and be amazing.
This really hit home with me and for some reason this has been on my mind all day. It isn't about trying to improve the things your bad at, you will always be bad at them and more in-efficient in the tasks you undertake. Something which would take a good person an hour, it may take you 4 hours, just sit there and think for a second of how much time you waste doing things your bad at? I get it if your just starting out and you have no income so you have to but for the people who are making money online, how much time are you wasting doing things your bad at? These tasks can always be outsourced by people who already know what they are doing and you can spend your time focusing on the things your good at! Now, ask yourself this question, how much time are you spending improving the things your amazing at?
By improving one skill and really mastering that down and knowing it inside out, you will have one skill which most others do not. A skill you can leverage and bring to the table, a skill which is HIGHLY valuable. You will not be a jack of all traders and a master at none, you will be the master of something.
So sit there and think, are you wasting your time improving something which your never be good at or can you spend your time making yourself better at something that your already good at?