I wouldn't say the little things are as important as the bigger things.
For example, increasing mileage from 30mpw to 40mpw is going to have way more of an effect on times than, for example, taking up foam rolling.
Personally I never was a fan of all of the obscure modalities. Of course, some work for some people. Ice never agreed with me and seemed to make things worse (outside of the first 48 hours following an acute injury). Stretching was a bit of a mixed thing and I much prefered drills actually and active movements. Ladder work was quite helpful for foot speed. Circuit training was a particular favourite of mine but it seems to have gone out of fashion now. You can build a lot of useful strength without bulking up using circuit training - there's a lot in it.
I don't think that knocking 11 seconds off is too big of an ask, especially given your age where you should be naturally improving anyway.
I still think that you should discuss this with your coach though as they're the one who's setting the sessions and you can't exactly go against them and do something else if you're on a team. You could supplement miles I suppose such as adding in an easy-steady 3-4 mile run here or there. But I still think you need to speak to your coach.
I always found work at race pace helpful - so getting used to 'floating' at that pace - running the bends, doing 120m - 150m at race pace, getting comfortable with it. Pyramid sessions such as 100, 200, 300, 400, 300, 200, 100 and so on.
Good luck and enjoy your track season.