The 'o' in all of those words is short, like in 'stop'.
'A' is not flat like in 'apple', but rounded like in 'argument'.
In English, for example, 'ate' - the a is a different sound from the a in 'at' due to the 'e' at the end of the word. This alteration of a vowel's sound doesn't occur in Croatian. (99.9999% certain.)
Variations on hello:
dobar dan = good day
zdravo = hello
bok = hi
Variations on thanks:
hvala vam = thank you
hvala = thanks
molim = please
Note the spelling of 'goodbye' - it has a funny-looking 'd' in it.
The best I can explain that is: pronounce it as dovidzenya.
Also, roll the 'r' a bit if you can on the tip/front of your tongue. (As opposed to with the back of tongue, such as in Dutch.)
The 'o' in all of those words is short, like in 'stop'.
'A' is not flat like in 'apple', but rounded like in 'argument'.
In English, for example, 'ate' - the a is a different sound from the a in 'at' due to the 'e' at the end of the word. This alteration of a vowel's sound doesn't occur in Croatian. (99.9999% certain.)
Its a nice explanation, I couldn't do better myself.