Translation:Dia duit. Comhghairdeas.
It helps a lot to learn the consonants and diphthongs. I found this helpful: www.angaelmagazine.com/pronunciation/introduction.htm
In here, mh and gh are both single consonants, and being broad they make a "w" and a gargling "g" sound respectively. The d can be a d or a j depending on dialect. So I remember ko-w-gar-jis connects to co-mh-ghair-deas. And I remember it's a gh (which I can't pronounce to save my life) because I need four English consonants in a row.
Finally spelled it right for the first time after learning all that. :D
When I took Japanese in school our sensei made sure we remembered things via awful mnemonics (our final translation was a tale of a guy telling his friend how he's learning english in an abandoned warehouse and delivering unlabeled packages at night to a guy behind a bus stop for his "teacher", aka "i accidentally learned english from a drug dealer," and the friend calling the cops because "your teacher is not a good person"). Nearly 7 years later I can still relate that entire final doubt I'll forget it any time soon. For comhghairdeas, the last 6 slides of this lesson I've been reading it as "Com(b) hg(retching noise) hair de as(s)"; why on earth one would comb butthair to tell someone good job I have no idea, but it's certainly been memorable when I need to spell it, oddness/awfulness aside...
This is probably not much help. But it has the word "hair" in the middle, and the "deas" is easy enough, so "hairdeas." That leaves the beginning as the toughest part, so I broke it down into "com" and a random hg. Like I said, that probably doesn't help anyone else, but it did work for me! Come hug Herr Deas? Okay I'm done. :P