PBW is right -- learn to use your gears in a way which permits you to cruise at a good (90-100 rpm, in my opinion) cadence. You can judge the effectiveness of your training regimen from your average speed over a given course. You can simplify your shift pattern by using your middle chainring most of the time. When riding my mountain bike on-road, I avoid using the inner chainring; when riding it offroad, I never use the outer ring.
If you frequently spin out of your top gear (unlikely), consider getting a larger chainring. If you struggle up hills in your lowest gear, consider getting a larger low cog. If you never use your top or bottom gear, consider converting to a closer-spaced set of ratios.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069