I recently started running again in July, after a year break due to a fairly bad Achilles tear, starting at about 15-20 miles per week, and now averaging about 30 with 3x5km, 2x10k, and a 15k on the weekends. I've since posted PRs of 19:20 5K in a local road race and 1:39:46 for a half marathon (both terribly slow by LetsRun standards, I know). I'm hoping to hit sub-19 for the 5K by the end of next July, but need advice on where to go with my training from here.