It's a criticism that means you often start a lot of things/tasks, but don't go through to completion. You perhaps get bored/distracted or simply lose interest. Then you give up on it and move on to some other task or hobby and the process repeats.

Complete or get it completed by someone else. The second one is more common.

"You never follow through on ANYTHING" You should use "anything" not "something" if you want to make a general statement The most common use of this is when referring to someones general attitude of not completing tasks, by using "anything", or when referring to someone always breaking promises by using "your promises". ---> "You never follow through on anything" ---> "You never follow through on your promises" "You never complete ANYTHING" "You never finish ANYTHING" As above, always using "anything" when referring to general statements. Apart from that change, both are grammatically natural but the 2nd is more commonly used.