For reliable RNA extraction from animal tissues, I would suggest using either the classic guanidinium–phenol (TRIzol) method followed by a column-based cleanup, or directly adopting a column/magnetic-bead kit depending on your resources and downstream needs. The TRIzol approach is popular and works well even for difficult tissues, but I recommend following it with a cleanup kit such as Qiagen RNeasy MinElute or Zymo RNA Clean & Concentrator to remove phenol and contaminants.

I agree with Sayad Mahmud Koli. I have had success with extracting RNA from "difficult" tissues such as bone, by first extracting with Trizol (until after the phase separation step), then taking the aqueous phase through a column-based cleanup. Bone is a fatty and fibrous tissue, and I was able to get RNA with a RIN of 7-8 and an A260/280 of ~1.9 consistently using this method. It's also worth noting that RNA extraction from any tissue requires very rapid processing after dissection. Either 1) homogenise immediately in Trizol and keep on ice/freeze while processing other tissues, 2) OR store tissues in RNA later, 3) OR snap freeze tissues in liquid nitrogen as soon as possible after dissection. Most issues with RNA quality stem from RNase degradation prior to extraction, rather than the method used for RNA extraction. Good luck.