RNA

One more thing, if you don't want to do DNase digestion, you can just design all primers for PCR to go across introns, so that genomic DNA does not get amplified during PCR. However, any genomic DNA will also add to your OD of the sample, so you can't standardize your results to the starting amount of total RNA. There are other considerations as well, so if you can, I would recommend DNase treatment.

You can use a commercial kit containing RNA-binding columns or you can just use Trizol. Either one works well. I don't know how much you already know about RNA extraction. The Trizol comes with sufficient instructions for RNA extraction. After extracting RNA, you just digest DNA away with DNase. With the columns you can do this when the RNA is bound to the column and then wash off the DNase, if you do Trizol extraction in a tube, you need to use phenol-chloroform to get rid of the DNase you have added. It also depends what you use as the starting material, as one of the primary determinants of RNA yield is the proper disruption of the tissues.The second most important thing is to prevent RNase contamination. You can do this by cleaning everything you touch with 0.5% SDS and then clean with 70% ethanol. Clean your gloves and pipettes with the EtOH periodically. Use only RNase-free tubes and filter tips and reserve reagents for only RNA work. Once you have the RNA, the best thing is to make cDNA, which is much more stable and easier to work with and you will be able to quantitate many genes form just one cNDA synthesis reaction, as in most cases 1/10 dilution of cDNA is sufficient, if you used at least 2 ug of RNA per 20 ul cDNA synthesis reaction.