If there is one thing the 2008 financial meltdown taught us, it is the value of a properly diversified portfolio. The second thing is that if you think you are diversified, you may need to check again. At the time, many thought they were, only to see losses across the board as assets that previously were uncorrelated moved together and sunk many a portfolio.

Today, figuring out what constitutes a diversified portfolio and, more importantly, how to actually assemble one can be a difficult and at times frustrating ordeal; every analyst and investment advisor has a different idea. To help you navigate these treacherous waters, we offer the following 10 rules of portfolio diversification.

1. Start with the end in mind. A diversified portfolio is not a one-size-fits-all product. Instead, it should be personalized, focusing on your personal long-term investment goals while considering your current personal circumstances. According to Michael Loewengart, senior investment strategist at E*TRADE Capital Management, your personal circumstances should take into account your current financial situation, expected future expenses and how far away from retirement you are. "The goal of asset allocation is to make sure the level of volatility in your portfolio is in line with your goals, personal circumstances and tolerance for risk," he says. Additionally, consider your temperament. If high-risk assets make you overly stressed, perhaps it would be better to stick with comparably low-risk alternatives.

2. Aim to reduce overall risk. Portfolio diversification has two goals, this being the first and what most people associate with diversification. If you have multiple assets in your portfolio, even if one is not doing well, you have others that are outperforming. As such, this reduces the overall volatility of the portfolio. "[Diversification] reduces your risk. Instead of being stuck in just one sector that may not do well at times, a diversified portfolio can sustain you and keep you in business," Michael Clarke, CEO of Clarke Capital Management, says.