Get them to open the offer Will they open your sales letter? That depends on the: 1. Envelope A No. 10 or monarch envelope look like personal or business correspondence. A 6-by-9-inch one stands out, but looks like junk mail. Envelopes with windows look more promotional than those without. 2. Teaser copy Blind envelopes sometimes pull better than those with sales … [Read more...] about Push the envelope