He told me that he had found it much more useful to save the extra money for repairs, emergencies, or future investment.

You will be glad you did.Have a strong and funded personal emergency fund as well before you start down this path.

They are just there in case of emergency. 

Some investors are looking at emerging markets and smaller cities for cheaper entry points and better cash flow.

Focus on emerging markets, cash flow markets, and appreciation markets for lower prices.

Here are some tips to help you make a successful investment:Strategies for Positive Cash FlowCareful Property SelectionEmerging Neighborhoods: Look for properties in emerging neighborhoods where prices are lower but expected to appreciate.

There are handful of crowdfunding lending companies emerged lately.They all seem to share a need to be an accredited investor to start investing.In order for an individual to qualify as an accredited investor, he or she must accomplish at least one of the following:1) earn an individual income of more than $200,000 per year, or a joint income of $300,000, in each of the last two years and expect to reasonably maintain the same level of income.2) have a net worth exceeding $1 million, either individually or jointly with his or her spouse.3) be a general partner, executive officer, director or a related combination thereof for the issuer of a security being offered.How strict is the accreditation requirement is being followed?

You must have money to service the debt on the property you do have, and to cover emergencies.  

You are one car breakdown or medical bill away from paying rent since you don't have an emergency savings.  

These provide stability and regular income, which can be crucial in retirement.Cash: 5-10%Keep some liquid assets for emergencies and short-term needs.Consider these additional points:Diversification: Spread your investments across different sectors and geographic regions to reduce risk.Tax efficiency: Consider the tax implications of your investment strategy, especially with your high net worth.Regular rebalancing: Adjust your portfolio periodically to maintain your desired asset allocation.Professional advice: Given your high net worth, it's advisable to consult with a financial advisor who can provide personalized recommendations based on your specific situation and goals.Risk management: Consider your risk tolerance and adjust the allocation accordingly.