Try prK treatment prior trizol incubation.

A nice way of obtaining good yield with good purity is through an Et-OH precipitation with a salt, you can find different protocols in the internet! You will always loose a bit of your RNA, however, I gain much better results by this method than with a column, plus many columns do not preserve small non coding RNA.

However as tip, when you add RNase free water to the column, use it at 37 degrees, you will see an higher purification with an higher yield,

also after the last washing add onto the column other 5 uL of RNase free water. Many times the RNAs remain trapped by the column!  

 A good way that you can I improve RNA purity without reducing its yield, is mixing TRI reagent protocol with column-based method. you should begin with TRI reagent and one time you have separated the phases you should transfer the colorless upper phase (containing RNA)  into a Spin column-based nucleic acid purification, I usually have used the columns from QIAamp Viral RNA Mini Kit (Qiagen), and follow the protocol of this kit, centrifuge 1300 rpmx 1min (the colorless upper phaseinto the column) and next two washes steps and elution with elution buffer AVE. I hope I have explained very well and you can get good result like us in our lab using this method.

Hello dear

Low amount of 260/230 is probably attributed to guanidin( guanidinium thiocyanate in Trizol) or mocopolysacharid, I propose that you should completely discard ethanol at washing step, briefly spin for 2 second and then collect residual with crystal sampler, make sure there is not any ethanol in the tube, after that put tube in room temperature in vertical position for 15 min,