Be careful to not reproduce in excess. This is the main thing. You don't want wealth to divide too rapidly between quick generations. Ensure you invest heavily in training people to teach them how to grow their wealth through age old tested ways: Gold, Real estate, well trained children. Ensure your accumulation rate is above your spending rate.
Modern day trusts too come to mind. Kennedy's, Clinton's, Rockefeller's and Rothschild's of the world.
Wealth doesn't last for long if you don't have the discipline for it. Most people who tend to lose wealth are generally the ones who completely lose a grip on reality. Deviate so far away from the very reasons that bought them there. Bad things happen from there on.