Divide & Conquer
Assets that generate more assets, like money, also are cause for generating liability. Keep them all separate - rental homes should be in a different entity than say, a marketing business.
Get Good Advice
Make friends with a local lawyer (much like a "family" doctor). The market is flooded with well trained and underutilized lawyers. Don't be afraid to negotiate fees.
Avoid General Partnerships
Do not 'do' general partnerships and handshake agreements. Did you know that any general partner can commit the partnership (and the other general partner) to any legal contract (like taking out a loan). All general partners are jointly and severally liable.
Don't buy Snake Oil
Always check references - three times is a charm. Never trust anybody who asks you to trust anybody else with your money and never trust anybody who promises to save you income taxes.
Watch the radar
Don't show off, don't brag about how much you have. If people think that you are rich - you will be sued. If you are unwilling to have a modest lifestyle (and many of us are not willing) then keep as low a profile as possible and don't title your assets directly in your own name.
Never Ignore a Lawsuit
If you are served - call that 'friendly' lawyer - always get good advice.