Tell them how your firm can solve their problems in a cost-effective way. That fancy typestyle might look classy on the sample sheet in the print shop, but it can be so hard to read that your prospective customers could toss your newsletter in the trash can. Keep your type simple enough and large enough to get your message read. Your prospective reader leads a busy life. Make it simple for him or her to understand what you're selling and how it will solve his or her problem.
Nothing turns off a reader faster than long dull columns of gray type.
Focus your readers' attention with creative graphic elements - art, photos, boxes, screen tints. These will help them better understand your marketing message. The best layout and writing can be undone by poor artwork. So don't be too clever. Too many newsletters wander away from their purpose and are cluttered with too many graphics.