This is my strategy for picking the best mutual funds.

First I find some mutual funds to look at. In my 401k, I have a very limited set of maybe a dozen mutual funds. So that’s pretty easy. In my Roth IRA, I have a larger selection. I have ETFs (exchange traded funds) in my Roth IRA. How I find ETFs to look at is looking at some different sectors that I am interested in, and pick some that list high returns. I try to avoid funds that are TOO narrow in scope. Instead of picking an ETF that focuses on some specific growing country, I chose an ETF for emerging markets. Where looking for the best mutual funds or the best ETFs, I use the same strategy.
Armed with a handful of ticker symbols I head over to Yahoo Finance. Lets use a few mutual funds from my 401k plan for examples. OPMSX (Oppenheimer Main St Sml Cap CL A), REREX (American Funds® EuroPacific Growth Fund® Class R4), and FBALX (Fidelity Balanced Fund).
First, I get a stock quote for one of the mutual funds (doesn’t matter which one). I will use OPMSX. When you get the stock quote for the fund. on the right hand side of the screen you will see a chart. Under the chart, click “max”. This will bring up a larger chart. Look for where it says “Compare: OPMSX vs”. I enter the other two mutual funds symbols into the box with a comma between them (“REREX,FBALX”). I also check the box labeled “S&P”. Now I click compare.
Now you should see a chart with 4 lines graphed on it, three lines for the mutual funds I chose, and one line for the S&P index. For my examples, the lines for OPMSX and REREX go way up, while the line for FBALX goes up only a little bit over the S&P index. Now I look at different lengths of time by clicking each of the links for 5y, 2y, and 1y. The charted lines for OPMSX and REREX stay up well above the S&P, while the FBALX line follow just slightly above the S&P line. This means OPMSX and REREX have both well out performed the S&P over time, and this is very good. OPMSX and REREX are two of the mutual funds I chose for my 401k retirement plan. FBALX is not.
I will find other mutual funds, and go through this same process. I will select a small group of diversified mutual funds that have all out performed the S&P over time.
This is how I choose the best mutual funds. It has been working for me so far. My 401k is worth over a quarter million dollars and growing! My Roth IRA is also doing extremely well.