In the events where you are a sponsor, you have most likely paid to be there. When walking past a booth, people are generally not waving their wallets around ready to buy something. This means that you should make them into audience two people rather than just ignoring all of the people not ready to buy. Nurture a relationship with the people who walk past you and over time, coax them into a position where they want to buy from you.
Use your sponsorship at an event to bring you a positive return on investment. Make sure to request a speaking position in return for you buying a booth. This will help you connect with more people and own the event. Make sure you know what you want to achieve when you step up on to the stage. Is it more customers? more speaking engagements? more emails for your list? Be clear and define what you want to accomplish before you actually do it.
If someone is paying you to speak, be sure to deliver. Make sure that you practice and make them look good. Get the audience involved with your presentation and it will create a more lasting memory of you. Make the best impression possible and that will have a line of people knocking on your door asking you to come speak at their events.
Provide value and value will come back to you.