How do I spell these sound effects?

I use a lot of sound effects in my daily communication. And since I like my fluthering to sound the same as my everyday conversation, I try to include words that substitute as my sound effects. But, I am not sure that the appropriate sound is coming across. Soo…

Wow: is this wow like “cow”, or wow that rhymes with Homer Simpson’s “doh”? Like “wow(h) Nellie”. If it is one or the other, how would I spell the other sound?

How do I write the noise that a raspberry (sticking one’s tongue out and blowing) makes?

Is ugh a disgusted sound, like for use when something is irritating or annoying? Or is it disgusted like “that mess is gross”? Would a gross smell sound effect be more like “yuck” or “blech”?

I just want to make sure ya’ll know what I am trying to communicate.