Gain enough know-how of your subject
No matter what subject you have to give a technical speech on, the first thing you should keep in mind is that you know enough about that subject. You do not have to be an expert in your chosen subject, but having an understating of its fundamentals will help you give an effective speech. The audience of every technical speech wants to learn things about the subject, and if your speech is directionless (and pointless), you will do nothing but waste your time and energy. If choosing a subject is at your discretion, pick one that you think you are well familiar with.
Analyze your audience
Once you have picked a subject that you think will grab attention of a particular audience, analyze your prospective listeners and assess how the speech as a whole can best be adapted to them. You should be aware that there could be people in your audience who know your chosen subject inside out. In such a situation, spending your time shedding light on basics of the subject will be meaningless, and will even bore the people listening to you. In order to satisfy your audience, you will have to dig deeper into the technicalities of the subject.
Using examples in your speech will cover up lapses and keep the audience engaged in the conversation. In order to keep general/non-technical people interested in the speech, examples generally help the speaker get his/her message across effectively.
Use visual aids
Using visual aids is a good way to get your point across. For a technical presentation, using graphs and the tables for stats and figures will help you cover most of your speech.