Well, I would have helped you but I'm not much of a Korean speaker =S From the very few I know and can tell, you have some différences between the to languages or some phonems only existing in Korean :
- The Ps, Ts, Ks are accented and bit a tiny puff of it, like in English... So you could either use some breathiness on them, or you can try a combination of short P/T/K with an H syllab
- For the R I am always doubting, but from what people told me, it can be rolled so or you go with usual Japanese Rs, or you make them roll by using short R + a longer R- syllab
- EO and EU : you could try to mess up with opening, so O and U (or yu) could be closer to Korean eo and eu sounds
- For Ls, use Japanese Rs
- Be careful with G, D and P, sometimes you can go with Japanese G, D, P but on most of words, it'll be likely like Japanese K, T, P
- J, JJ and CH = you will likely use Japanese "CH" sound to get enough close
- NG = use simply an N (try to make it lnog when it's possible)
- For AE, you can either use opening on Japanese E or try the combination short A + long E
Anyway, you can check this http://en.wikipedia.org/wiki/Help:IPA_for_Korean or like Twisted said, look at some videos with Native speakers explaining it, or tutorials =3