I keep forgetting to follow through on small plans with a friend and it's adding up

Lately I've been noticing a pattern where I'll agree to something simple like grabbing coffee or helping with a quick errand, then something comes up or I just space on it. It's never anything huge, but it's happening enough that I'm starting to feel bad about it. I don't want them to think I'm flaky on purpose. When I do remember at the last minute, it feels awkward to cancel, so I end up saying nothing and hoping it goes unnoticed. That only makes the whole thing worse. I'm trying to figure out how to get better at keeping these little commitments without overthinking it. Anyone have a system that actually works for staying on top of low-stakes plans?