No matter what grit you want the final finish to be, overshooting it and coming back down makes CERTAIN you have all the previous scratches out. So you end up with a very clean, uniform satin finish. Even if you only go one grit further, say 800 then back to 600, it helps. Try it, you'll like it! You really can tell the difference, especially with an opti-visor and/or in bright sunlight (which both tend to show any little inconsistency).
I'm sure you've read about alternating the direction you sand in-between grits; it makes it easy to tell when you really do have the previous grit's pattern smoothed out. I've even gone so far as to alternate with each grit... it's time-consuming and may or may not be worth it, but it does help me get every last rascally swirl/scratch.
Another tip... when you're ready for your final step, clean the blade as good as you can(hot soapy water, then wipe down with alcohol works good for me) and use fresh, DRY paper on every stroke. This nearly eliminates stray grit or swarf causing a tiny flaw. You don't have to apply hardly any pressure, just focus on keeping the scratches nice and straight.