More often than not, people take editing to mean "cutting out" things and ideas. What is truly intended by 'editing' is knowing what to leave and what to scrap. Watching out for fluctuations in grammar is a #1 priority, all things considered. To do this, ensure all your writing points are fleshed out, and read and re-read your draft for fluidity. Then, get started.
1) Make a point of tackling vocabulary first. The reason for this is so you can understand the intention of the document at hand. Diction and word choice reign supreme as you glide down your written work to determine if your tone and style are reflected as accurately as possible.
2) Take note of the verbs and the objects of every sentence -- so that they correlate with the place and time of your narrative. For example, if you are speaking in present tense about a car chase, you may want to include power verbs (e.g. careens, darts, corners). Then, you should check the object: is it detailed and specific? If you wonder what is meant, then you need to tighten up the language there.
3) Find punctuation errors line by line - after you have taken into account the plot or point of your written work. Punctuation can add as much meaning to your goal as an adjective or adverb, and should be treated with high regard. Tell your story first; punctuate second.
If this short list helps you to develop into a stronger reader, then you can look toward better writing skills ahead! Keep up the good work.
MJ Text Style