In my opinion, spring is the most effective time to market, since their lawn is fresh on your potential customers mind.
www.rndsigns.com can create professional looking flyers or door hangers for you to pass out to get started canvasing in your target neighborhoods. They also offer postcards, brochures, newsletters, posting lawn signs and more. They offer great prices for quantities between 500-1,000. They also provide layout ideas and free design services included in their price. Just pick a layout idea and tell them what you want it to say and they put it together for you.