How can I burn CDs that are larger than the standard 74 min CDs? Such as 80 min and 90 min CDs?

Your CD recorder must support the overburning feature and this type of media. Some recorders support 80 min media but will not support 90 min or 99 min media.
Please check the points below:

1. Please make sure to update to the latest Nero 7 release.
Recommend: Nero 7 Premium or Ultra

2. You need to have the latest firmware for your CD recorder model, as it will contain information to enable overburning. Most importantly, it will contain read/write strategies for new brands of CD-R and CD-RW media brands and can resolve many issues you may otherwise run into.

3. To overburn, you have to burn in either "Disc-At-Once" or "Disc-At-Once 96" write mode. Do not use multisession mode, it is not possible to overburn.

4. Enable overburning in Nero's "File > Preferences > Expert Features" (if you use Nero Express, do so from "More > Configure > Expert Features") and deactivate/disable "Check for correct disc format" from within Neros "Files > Preferences > General" (or from within Nero Expresss "More > Configure > General settings").

If you enable overburning in "Expert Features", you should use the settings below, based on the size of media you are working with:

For 80 min media set to 82:00
For 90 min media set to 89:30
For 99 min media set to 99:54:74
Important Note

Keep 99:54:74 min entered and it will always enable burning to the max.

Good luck,