My editing style, for my writing, is a lot like clearing the brush.
Editing seems to be done in layers, with larger glaring issues to be handled first, and then more of the intimate editing later. Sometimes the larger issues are so massive that you can't help but miss out on the smaller ones.
What do I mean by clearing the brush?
Imagine you just bought a little lake cabin. You got a great deal for it. It hasn't been lived in for 2-3 years. The bushes in front have grown to the eaves, the grass looks like a wheat field, and last year's leaves have blown into the corners.
What's the first thing you do?
Mow the grass.
Once you do, you discover a small path made of solid gold leading from the front down to the lake.
Let's tackle the leaves.
As they're all cleared away, you notice a small door leading to an underground shelter, which is stocked full of canned goods, bottled water, and even has an assortment of games like a pool table and table tennis.
Excited, you trim down the bushes, only to discover that a lot of sunlight pours into the cabin's interior and it appears larger than what it really is.
After all this, you may handle smaller projects.
The point is that editing a novel--much like clearing the brush away--is a daunting task and shouldn't be taken lightly. But taking it piece by piece, just like anything else, will help you to accomplish your goal. As the saying goes, how does one eat an elephant? One bite at a time.