It strikes me that Irish is spoken with more of a closed mouth than English. There are more front vowels than back vowels and there are palatalised consonants. Slender r is a challenge. It strikes me that you can read out a passage in Irish better biting on a finger lodged between your upper and lower teeth. That keeps the mouth from opening too wide and should help the pronunciation of front vowels and slender consonants. At the same, you can still pronounce the back allophone of "a" while doing so. The reason why different languages have different accents is that the native speakers of various languages get used to a general mouth shape. in Irish the mouth is mainly closed.