Use equations sparingly if at all - audience members not working in the research area can find them difficult to follow as part of a rapidly delivered presentation. Avoid derivations and concentrate on presenting what your results mean. The audience will concede the proof and those who really are interested can follow up with you, which they're more likely to do if they understand your results. Finally, and this is critical, always, always, always preview your slides. Timing your talk Don't deliver a 30-minute talk in 15 minutes.
Nothing irritates an audience more than a rushed presentation.
Your objective is to engage the audience and have them understand your message. Don't flood them with more than they can absorb. Present only as much material as can reasonably fit into the time period allotted. Generally that means 1 slide or overhead per minute, or less. Talk at a pace that everybody in the audience can understand.