Are you good at editing your friends’ writing, but when it comes to your own you suddenly experience what I call editor’s block? Editing your own writing can be more difficult than editing text someone else has authored.
You’re “closer” to your own work than anyone else; therefore, you fall into the trap of being blind to your own mistakes. This is called “proximity blindness.” Symptoms include the sudden inability to delete unnecessary words, to notice misspellings, to fix misused punctuation and to provide a fair analysis of your overall structure.
A fresh pair of eyes will suddenly see what you cannot. Eliminate proximity blindness. Hire an editor.