Primer design - Primer design for RT-PCR (Mar/16/2002 )

Could anyone give me tips on designing my primers for RT-PCR? I will be studying the expression of various cytokines, NOS and membrane receptors from the monocytic cell line THP-1. I intend using Tri Reagent (Sigma) for RNA extraction, then proceed with reverse transcription and finish with with my PCR.

For RT-PCR primer design, I usually follow these lines:
1) pcr product site 200-400bp
2) span a intron within amplified region
3) primer length: 18-24mer
4) non complementary between two primers
5) non hair-pin within primeer
6) use some software like MacVector(for Mac), Omega(for PC), and others (there are many)

Hope it helps