Make it BIG!
When applying text to your slides make it big enough for the people in the back of the room to see. Going back to the earlier tip about one point per slide this frees up a lot of space to make big text. Forget everything you have heard about the “rules” of powerpoint the 3×3 or 4×4 or seven words per line and no more then seven lines or any of the other made up rules.
If you must use bullet points limit them to one sub bullet section
Here is what I mean, This one is ok
TITLE
Heading 1
- Bullet point one
- Bullet point two
Heading 2
- Bullet point one
- Bullet point two
NOT OK
TITLE
TITLE
Heading 1
-Bullet Point one
- Sub bullet 1
The more bullet points you add and the deeper you get the smaller the text becomes. This makes it even more difficult for those in the back to read.
Display type should get attention and get the point across. Big gets noticed and read, and big makes for easy contrast with small, aiding in guiding the viewers eye. A technique called Kerning (adjusting the space between individual letters) becomes an issue with text at larger sizes because the spacing that worked automatically at a smaller font point may be unbalanced at a much larger point size, but since you are not using so many words at the larger size, adjusting a few letter pairs here and there (such as WA, etc.) will not be such a big deal. Common letters that may need to be kerned include: A,R,T,V,W, and Y. This may seem like a minor thing,but it all adds up.
Ligatures also need to be watched. Ligatures happen when two letters are joined into a single character. Common ligatures include: fl, fi,ft,ff,ffl,ffi
Ligatures and Kerning can be adjusted in the settings or your slide ware.
So how big should your text be? Here is a tip form Slide;ology Take the diagonal size of your computer screen, say it is 20’‘ then measure off that distance in feet from your screen. Start your slide show, if you cannot read something from that distance then it probably wont be able to be read at the back of the room. You can also put your presentation in slide sorter or light table view and take it to 66% size, if you can still read them then your audience should be able to as well. Still in doubt? Try to get to your location early and set up, then stand in the back of the class room and flip though each slide see how it looks.

