First of all it depends upon the system of PCR machine you have, then selection of companies like; ADIAVAT, Qiagen, Applied sciences, Invitrogen life technologies etc..   

Hi, I initially suggest to examine fitness of synthesizes cDNA by its amplification by reference gene (Also use negative or positive control). In fermentase cDNA kit you have positive control. Then, try companies.

Hi, about RNA/DNA extraction I thought about the RNA and DNA spike, (an example http://www.bioline.com/sg/dna-extraction-control-670.html, http://www.bioline.com/au/rna-extraction-control-670.html), then you can buy the primers to check the spike extracted throughout the RT and PCR. I used this method for microRNas analysis in serum (example http://www.exiqon.com/rna-spike-in-kit)

You have to study kits and strategies for the different samples and choose the companies that offer you the best at "low cost". Hope this can help you, good luck!

Hi, you can use internal control genes eg., beta actin, etc. as controls specially in real time pcr experiments.

Thanks for the answers. I have tried several things and I find that commercial Bioline DNA and RNA extraction control kits are the most suitable for my lab.