The more strikingly visual your presentation is, the more people will remember it. And more importantly, they will remember you. — Paul Arden
Good graphic design is not about decoration or making something look super fancy.
Design is about making communication as easy and clear as possible.
The rule of thirds is a principle of the Golden ratio with broad application as a "rule of thumb" or guideline which applies to the process of composing visual images such as designs, films, paintings, and photographs. The guideline proposes according to the principle of the Golden section search that an image should be imagined as divided into nine equal parts by two equally spaced horizontal lines and two equally spaced vertical lines, and that important compositional elements should be placed along these lines or their intersections. Proponents of the technique claim that aligning a subject with these points creates more tension, energy and interest in the composition than simply centering the subject. - Wikipedia
Resist the temptation to put your entire thesis on your slide. Your slide should convey the essence of your thesis and is meant to complement your spoken presentation.
Only include things that are:
image source: http://drmarkwomack.com/images/serif-vs-sans-serif.png
Using colour is an important aspect of delivering your message. Colour can help convey emotion, but keep in mind that colour association is culturally specific. For example, the colour white can mean purity in some cultures, but in other cultures white is associated with mourning.
It is a good rule of thumb to use colour sparingly (2-3 colours maximum).
Things to think about:
Contrast - shoot for high contrasting colours. Avoid black text on an all white background as that can cause glare and eye strain.