I like to make the most out of the interesting features avaliable in font design. 2 ways to make fonts more interesting are Ligatures and Alternates. The special glyphs are called open type features.
Ligatures are :
Two or more letters are joined together to form one glyph or character. This is a fun way to make intersting shapes and curves in letterforms. Some fonts have lots of ligatures while others have none. They are automatic, and will join when typed. If this does not happen then you ligature setting is turned off in your design software . Every software is has a different way to turn them back on.
See this video that explains it in detail: Here
Alternates:
Alternate letters are extra letters that can be swapped in to replace the standard letter. Usually this alternate letter is a more ornate unique letter.
Sometimes they are graphic alternates (letters with pictures in them). To access alternates is again different in different software.
For adobe design software you can just highlight the letter and the alterante letter will appear.
See this video for more details: Here