What you need is the right rep. Why? The retail business is all about relationships with retailer buyers. YOU don't have them and the rep does. The great news is that most reps only charge commissions so you don't pay a penny unless they actually sell something for you. If a rep ever asks you for a retainer - find another rep. However, given the work required to get a product in, a rep will typically screen out products that they believe have a limited chance of success.
If you are contacting a lot of reps and no one will pick up your line ask them why. Reps know all the ins and outs of retail and they usually have good gut instincts and understand the consumers in the product category.
If you have your prototype, brand name & logo, packaging, product liability insurance, logistics in place, sales presentation and brochure complete -- now it is time to reach out and get the right reps for your business. Ask around. Join Linkedin, www.linkedin.com and search for groups that are relevant to your business. If you are in the pet business, consumer electronics, or food category, contact us at email@example.com.
Good Luck & Good Selling!