To build that relationship, the most important element is eye contact.
Also, confident posture and body language is crucial, especially the way you move and the way you use the space around yourself, being able to approach closer towards the audience, yet not to be perceived as aggressive or pushy.
Be honest and be spontaneous!
It is less important to deliver the perfect presentation and it is much more important to appear human! That way audience can identify with you. Empathize. Feel close and connected. By being more ready to step into your shoes, they will be more open to listen to what you have to say.
Do not hesitate to put in some humour, but keep it on the level that will not be offensive for anyone and that will be tied into your presentation, instead of being distractive.
Most important: Keep it interactive! Keep people involved. Ask them questions. Give them time to think. Allow them to ask you questions. Look for their feedback and be aware of their reactions. Don’t forget – they are just people, just like you, and that human effect is the strongest link that you have towards your audience.
Beautiful example of connecting with audience can be seen in Benjamin Zander’s TED talk – he is using passion, humor, surprise, and more than anything, radiates honesty and warmth: