Provide the most accurate information about the products you promote. Never exaggerate to quickly make a sale. Your audience will see through it and they will turn their backs on you. Instead, if the product you are promoting isn’t perfect, say so! It never hurts to explain the downsides to a product because this just proves to your audience that you are being completely honest with them. Also–this is very important–be transparent about your relationship with the merchant! It is legally required that you disclose your affiliate relationship, so any time you share an affiliate link you need to let your audience know. Make sure you are following the latest FTC guidelines here.
But I think the biggest deciding factor in this, goes back to the site as a whole and all of the other posts. Are the genuine? Is the blogger constantly trying to push products? I’d like to think I’ve been doing this long enough that my audience knows I’m not out to make a quick buck – and I think even relatively new bloggers can prove this based on their other content.