Transitioning from one game to the other is not necessarily easy. I truly enjoy the both games but have Omaha requires a higher degree of discipline and focus in my opinion.
Since everyone is holding more cards, player have more options. When you have something like two pair or even a set with a board that has possible straight and flush options the
odds of someone completing the straight of flush hands increases greatly when compared to holding just two cards in Hold Em.
If I had any advise to give, it would be about pot control. If you hit the nuts on the flop it might not be the nuts on the turn still, and probably won't be the nuts on the river. So, don't get all raise happy because you have what was the best hand after the flop. There are still two cards to come Omaha is truly a game of draws. The nut hand is likely to change on every street.
Also be careful when playing straight and flushes against a paired board. A paired board in Omaha generally means full house.
Avoid counting possible dead cards as outs. For example, if a card can give you the nut flush but would also pair the board yielding a possible full house should not be counted as an out. It is likely someone out, but probably not yours.
Do some research and be prepaid to jump into the action. It can be fun and profitable. The games are different, so adjust accordingly.