Drop the bulldozer style of negotiating
While it may make great TV, the aggressive negotiating tactics seen on the likes of The Apprentice or Dragons' Den are old fashioned. We now live in a collaborative world. Working with the other side and focusing on their needs will make them more likely to respond to what you want. Bullying will rarely get you anywhere. If you take advantage of someone in a deal, they never forget it, and no matter how long it takes to get their own back, they will.
Dispel the fantasy of others' bargaining power
SMEs and entrepreneurs often feel that they are at a disadvantage when negotiating with larger players, believing that because the other side is bigger they hold all the aces. But there are many sources of bargaining power, and they are rarely all stacked in favour of one side. For example, while you may be a small company, you could have expertise, contacts, reputation, or information in a particular area which no one else has. Think about what you have they might want and use that to get a realistic handle on the balance of bargaining power between you.
Ask for what you want