For starters…

• Stretching the type (horizontally or vertically).
• Trying to fake a heavier weight by stroking the outline.
• Justifying text in a way that results in huge gaps in between words (and thus, rivers are formed).

- — - — - — - — - — - — - — -
Will food for type.

not using the proper quotation marks/apostrophe. however, as with all sins there are always exceptions to the rule. for example: To Squoosh™, or Not to Squoosh™?

Crimes against typopgraphy

letterspacing blackletter

Having your head inserted in a dark place and spinning off theories about good and bad typography.

My typography teacher would say: "don't hurt the type" meaning not to stretch the type, and people did throughout my entire college course.

I would have to say things that 9/10 times don't work for beginners are:

Modifying glyphs for logos, unless you can really get inside of the typeface and work it from the inside-out

Stretching type, it always looks...stretched. Much better to invest in condensed or extended weights

Type on a busy background or a background without adequate contrast make it illegible. Happens way way too much

Using Novelty Fonts in the wrong context can lead to disaster. Comic Sans and Papyrus are the easiest targets, but I think I will slaughter whoever typesets something in Bleeding Cowboys or another DaFont.com special next.

Script Fonts don't replace real script. It's so hard to set script fonts convincingly or even decently unless you invest in a professional font family with plenty of alternate characters and swashes. And then it takes a preposterous amount of time to tweak and finesse the words individually. And then you still run the risk of it being hard to read, or virtually illegible to a non-english speaker who may not have extensive recognition capability of hand-written latin characters.

Reversed type with poorly sized coloured boxes behind them. As I understand it we value the top half of a letterform more then the bottom, so anything that would diminish the recognition of the top of a character would diminish the legibility of that character. If you're going to put a box behind it and make it white, make sure you have enough of a box so it's still readable.

FULL CAPS are always the wrong answer. Small caps are like a beautiful little kitten when handled well, full caps are like a dog who has chased a muskrat through a ditch and then wants to cuddle with you.

creative punctuation or lack of it see if you enjoy reading this sentence but guess what its not just one I actually ran a bunch of sentences together here I am so avantgarde or whatever because I dont use periods

You're not going to change the world or appear creative and 'cool' because you ignored all normal conventions for writing english (or whatever you may be writing), no, you'll look like a fool.

Using hyphens everywhere looks bad. There are times for en-dashes –, and em-dashes —, and hypens -; learn their proper context and don't just use the hyphen for everything.

Not using ligatures makes your work worth less than the paper it's printed on.

U sing Microsoft W ord or P owerP oint F or Anything leads to horrible kerning and it's no acceptable for presentations, resumes, or pretty much anything other than draft versions or spellchecking work. If you need to do a presentation, I think every designer has the tools to make a PDF, and you can kern your letters like a real man/woman! I hate seeing people who ought to have type sensitivity (like my typography teacher) using powerpoint and think it's okay because that's just the standard of quality powerpoint does. Dont' settle for inferiour product, because you're lowering your standards, and then other lower their respect of you to those same standards.

There's my little rant about the type-related sins that make me annoyed. It's hard sitting in a room full of 40 designers and being one of maybe 5 who actually care enough about typography to open up a glyphs palette, or figure out what these Small Caps things are. Type is communication, and improper type is improper communication.

Reading the rules of typography in textbooks and assuming that they’re always right.

>FULL CAPS are always the wrong answer

What if you're Stanley Morison, or Bruce Rogers,
or even Aldus Manutius?

There are too many… :=)