I brush after breakfast, and before bed. I only use baking soda. I floss before bed.
The most important thing for me is actually to restrict the time of brushing to 2 minutes...I'm at risk for obsessive-compulsive behaviour regarding teeth.
When I first got my braces, I became seriously plague-a-phobic. I mean, I would spend hours (yes, hours!) in the bathroom, obsessively removing as much plaque as I could.
I brushed them so vigorously, I risked damaging my gums. Plus, it probably wasn't very healthy to be using so much fluoride (toothpaste) each day.
And my gums were always in agony, from vigorous brushing. Of course, at the time, I thought I wasn't being vigorous
enough.
Now that I brush within 2 minutes, my teeth have never felt healthier, never looked cleaner, and they never ache.
I should point out that my refined sugar is confined to short bursts -- I'll occasionally pig out and eat 10-20 cookies at once, but only once a month. I've started my 30-day "no sugar" trial, during which I hope to kick the habit for good.