well, lol, us 'veteran players' usually manage to keep 100% morale (if they wanted anyhow) and are able to rake in the money with high taxes (usually 69% or 79%)
Depending on the version (DL/DA/TA) and tech tree (TA), Xeno Entertainment (+15 morale) is an important early grab as can be Habitat improvements (PQ 11+ worlds get a +10 morale boost), and Neutral Alignment (another small morale boost across the board)
Throw in a morale structure or two, and a morale resource, and you can usually maintain that high approval rating without even a hiccup.
As someone was pointing out in another thread though earlier today, once you hit max population, morale loses its importance as you only need to be able to win elections.
I've known players that have actually been able to get 100% approval with 100% taxes. Its not cost effective obviously, as you need LOTS of morale structrues, but hey, thats not the point right?