i got new tall boots recently too!! to break them in just like wear them around the house walk up and down the stairs and of course ride in them as much as you can!!!!
you can condition the inside and outside too. that helped meee. i ride alot of horses so just riding that much got mine to break in in like a week!! it was really fast haha. but i have rectellines so they break in really well. my ariats took like a year. also wear them around the barn and walk around in them as much as possibleee and also you can bend them back and forth at the ankle and that will probly help!! xoxo
Walk around the house (particularly up and down the stairs) and use baseball glove softener around the ankles! (Use sparingly as in excess this can dull the gloss in the leather)
^You can probably find it at any local sporting goods store. Just ask a sales associate. It helps break in new baseball gloves, so I imagine it would work with your boots.