Alternatively, umbrella insurance may offer cost-effective protection.

Also, your total returns go down without any leverage because you lose the multiplier effect of appreciation.Now, to answer your question.

Most come out ahead over an extended period of time by buying better quality assets where they perhaps have to leave some capital in the property but find themselves able to sell for real gains or refinance out appreciated equity and scale more effectively that way. 

In your opinion, what is the most effective way to establish an LLC? 

All these will effect long term appreciation and rents.  

A good real estate accountant can save you thousands of dollars by leveraging entity selection and formation, tax deductions, cost segregations, bonus depreciation and tax planning.I recommend finding an accountant who specializes in real estate taxation, business taxation, financial planning and tax planning.You may want to consider working with your accountant remotely to expand your options.I would also recommend looking for a accountant willing to work with you throughout the year.

Any tips on targeted marketing, effective lead generation, or even some "outside-the-box" tactics?

Start small, network with other investors, and use tools like BiggerPockets calculators to analyze deals effectively.

Finally, select the market that best aligns with your goals.

Also, check to see if your jurisdiction is practicing "Just Cause Eviction", which went into effect statewide earlier this year for municipalities that which to opt in.