I second the recommend to get a computer. I'd never had one until I bought my latest bike, which came with Flight Deck compatible brifters. I found an older model Flight Deck on eBay for cheap so I went ahead and got it, just thinking it would be a neat toy to have but not particularly useful. I was amazed at how I'd been apparently mashing for years and have started to make a concerted effort to keep my cadence up, and I believe it really is helping. I'm still a bit of a masher, most comfortable at about 60 RPM or so, but I'm trying to improve that by deliberately spinning it up a bit by staying in a lower gear than I ordinarily would.