Don't beat the market. BE the market by investing in a broadly diversified portfolio of low cost tax efficient index funds. Because when you have a plan, you know what to do when markets fall. 

 Vanguard's John Bogle said it best: “the shortest route to the top quartile in performance is to be in the bottom quartile of expenses.” 

Investing in funds with low turnover and taking advantage of tax loss harvesting saves money on taxes that goes towards your goals. 

The overwhelming majority of research suggests that most active managers underperform their benchmarks. 

90% of Investment return comes from asset allocation according to a landmark paper published in 1986 called “Determinants of Portfolio Performance,” by Gary P. Brinson, L. Randolph, and Gilbert L. Beebower,

Lowering volatility in a portfolio is less stressful and can lead to a greater return according to Kiplinger's article Your Real Return.

Opportunistic Rebalancing says that rebalancing your portfolio during optimal times may add return and reduce fees.