You will be unlikely to interest a homeless man in a new car, until he's fulfilled his basic need for shelter first - unless he plans to live in the vehicle, I suppose. Understanding this principle and seeing how it applies to selling, will enhance your sales performance zillion-fold. Sell one thing at a time and concentrate on that. Don't confuse, don't stray from the point, do stick on the blinkers and keep to the target and the matter in hand. Don't overlook the obvious.
People respond to simple commands.
Serve up testimonials next to your products or your newsletter sign-up form. Use colors that convey the right image and incite the right actions. Use black and yellow. Dark blue, maybe a bit of gray. Blue and green - which so many large corporate sites have adopted.