I don't have too much general philosophy to add to this discussion; on the other hand, here is a practical tip from Tom House that has worked, and worked, and worked, for my son:
Early in a game, try throwing a high percentage of 0-0 breaking balls. By midway into in the game, change the 0-0 pitch to a higher % of FBs.
The upsides are: Very few batters are sitting on, or will swing at, a breaking ball on 0-0. Thus, if the pitch is a strike, it's almost a free strike. If the 0-0 breaking pitch is a strike, the hitter's attention has been altered and he is set up for your 0-1 FB. Even if the 0-0 breaking ball misses, it is a relatively risk free spot in any sequence to "practice" getting the breaking ball into the strike zone. Most pitchers justifiably hate to go 2-0 or worse with a hitter, but 1-0 is not that stressful.
The downsides are: If the pitcher really doesn't have a decent breaking ball, the opposition will realize that quickly and go up 1-0 far too often. Then, they'll too often be okay sitting on the FB. The reason for adjusting the strategy mid-way into a game is obvious--hitters adjust, so pitchers should remain ahead of hitters' adjustments.