It would be best to go for lithium chloride precipitation.

https://www.thermofisher.com/my/en/home/references/ambion-tech-support/rna-isolation/general-articles/the-use-of-licl-precipitation-for-rna-purification.html

Add 1/10 vol. of 4 M LiCl  and 3 vol. of  100%Ethanol.

Leave for 2 Hrs at -20°C or 30 min at -70°C.

Centrifuge at 4°C for 30 min at 10000rpm

Wash pellet with 70% cold Ethanol (-20)

Centrifuge at 4°C for 30 min a 10000rpm

Dry under vacuum for 5-10 min

Resuspend in your buffer ( sterile water or other, add RNase inhbitor).

Good Luck

Hello

Daniele answer is excellent

I would simply add to it be saying that yes for limited quantities of RNA (in particular) apart from precipitating @ -80C with salt and 3 volumes of ethanol 1ul of 1mg/ml to 20mg/ml molecular grade glycogen as a carrier (this is non specific so anywhere in that range is acceptable) will improve the recovery of your RNA:

Typically if your expected total volume of RNA is 1ug to 10ug adding 1ul of glycogen in addition to salt and ethanol will  increase your recovery (typically) from > 80% to 95 ~100% in my experience

In addition, when you add glycogen to the ethanol salt mixture, pipette up and down to mix and then incubate @ -80C after spinning your pellet is larger and much more opaque: This will give you the confidence to remove most of the supernatant, add 0.5mls of 70% ethanol (in a 1.5ml eppendorf) and then vortex to wash. This will much more effectively desalt your pellet

In that regard I would also say that using room temp 70% ethanol, contrary to received wisdom is actually OK for RNA as the RNA is relatively stable in ethanol and as a pellet: The advantage of using room temp 70% is that it will more effectively desalt your pellet

I will add 1 word of caution: LiCl specifically precipitates RNA as opposed to genomic DNA (not true of sodium acetate or ammonium acetate) so gives you the best quality RNA. However, LiCl can inhibit down stream enzymatic reactions including RT so for theat reason has fallen out of favour a bit

I would say if you do precipitate with LiCl add Glycogen and then desalt as described by vortexing with room temp 70% ethanol. This in principal and for whats its worth in my experience will give you the best of both worlds   

Dear Dr Laurence,

Appreciate your detailed reply. I would just like to mention that LiCl precipitation of total RNA is method of choice in my lab. The precipitated RNA is routinely used to reverse transcribe mRNA into cDNA that is then used for antibody library construction. We have not observed ill effects of LiCl precipitation on RT. When we began with library construction, we only employed TRIZOL method to collect total RNA but did not get good quality cDNA suitable for library construction. When we reprecipitated the RNA with LiCl, the quality of cDNA improved dramatically and we managed to construct very complex libraries.

Dear Syed

I will bear that in mind. Thanks for the constructive feedback !

Thank You Dr Laurence and Dr Syed  I'll try Dr Daniele's solution.