how to avoid sounding like a ____

Avoid all caps and use fewer exclamation marks.

Say nothing and have your characters do the same.

You may have noticed that different people react verbally in diffeent ways. If you told several people that you had won a lottery jackpot, then you could expect reactions ranging from a ten minute collection of superlative to a shrug. Someone who doesn't know you from Adam would have no reason to be enthusiastic about your good fortune. Keep that in mind and have some of your characters react suitably.

I think your problem is illustrated by the use of the word "spastic".

Not only do a lot of people find it offensive, but you've had to define how *you* use it in your first sentence, because you are aware that people won't understand you otherwise.

If you feel your vocabulary is lacking, work to expand it.

If you're talking about something happening to a character in a story you're writing, or if you're writing about yourself in an essay, describe the feeling.

Just some of-the-cuff examples: Instead of "I felt horrible," you could say, "My body shook and I couldn't think." Or instead of "That was amazing," write, "She grinned and clapped her hands until they were sore."

I find the word "spaz" offensive too. Don't use it, please.

All-caps can be effective when used appropriately, but they are tiring when over-used.

My first thought when I read the question was that you need to look for specifics rather than superlatives. In other words, something may indeed feel WONDERFUL, but what kind of wonderful, precisely? Stormie in her post up-thread gave some excellent examples.

Try writing some poetry. Make yourself look for very specific qualities in your word choice.

I think you need to build up your vocabulary. Spaz/spastic (yes it's offensive) seems to be the only word you could think of to explain what you meant, but even that didn't really fit because you then went on to explain what you really meant.

You could have said:

"How to avoid sounding like...

...an overly emotional airhead
...an idiot
...someone who's getting overexcited over silly things
...a drama queen
...a drunkard
...a daytime TV presenter
...a game show host
...someone who's taken too much cocaine
...roadrunner on acid"

or any number of other ways to explain what someone sounds like when the USE ALL CAPS AND TOO MANY EXCLAMATION MARKS!!!! (To answer your question, yes writing like that does make the character in question sound like a game show host on cocaine. Or like they're standing on a hill yelling the words through a loudhailer.)

Reading more will help you develop better ways of expressing yourself, without even trying. Practicing finding different ways to say the same thing also helps. This will help you also with finding better words that amazing, wonderful, etc, and feeling like you need to capitalise stuff and add exclamation marks. You'll find better ways to express all of that.

Any forum that allows a thread title such as this to stand is not one I wish to frequent. It's been pissing me off mightily every time I see it, so I'm out of here.

Yeah.... not happy about the title either. Can a mod change it? It's difficult to avoid being reoffended when the title pops up every time someone posts to the thread.