I sailed through Calculus, Diff EQ, and Engineering Math, but trying to pick out which financial numbers to pay attention to on a mutual fund statement or Morningstar report makes my eyes glaze over. There are a gazillion funds out there, and even when I narrow it down to a single fund family I have trouble determining why I should pick one fund over another.
That's easy: asset class, diversification, and expense ratio.
What type of asset is the fund invested in? E.g. for stocks, small vs large vs mid vs blend, growth vs value stocks, country. A fund like the Growth Fund of America (RGABX) is a large cap US stock mutual fund with a mix of growth and value stocks. For bond funds, pay attention to average duration and credit quality. Some actively managed funds will move assets around and try to time the market; avoid these, they don't know what's coming any better than you do, and it makes what you're trying to do (understand your portfolio) an order of magnitude more difficult. Some funds have a mixed allocation between multiple types of asset classes, but stick to set targets like 65/35 stocks/bonds. These can work well as most or all of a portfolio if you're generally happy with the fund's allocation, and they offer a bonus of making rebalancing easier. The tradeoff is they're harder to customize.
How diversified are the investments in the fund within the asset class? The more diversified, the better. Most funds other than hedge funds are a fine choice here.
What's the fund's expense ratio? The lower the better. Look for 12b-1 fees, these are marketing and advertising costs the fund incurs. This is an outright waste of your money. Good mutual funds don't need to advertise (like MMM's "Position of Strength" concept). Also look for loads, and commissions you might pay to buy the fund within the accounts you have. If you would have to pay a commission but really want the fund, look for a commission-free way to buy it (i.e. set up a new account with a provider that lets you buy it commission-free).
If you're still having trouble picking funds, it's probably because you don't have a good plan for what you want to invest in, so everything sounds good to you. It's like trying to buy a computer without knowing what you're going to use it for. So if you're confused, stop looking at mutual funds entirely and get a bit introspective.
For instance, (and this is all hypothetical and not what I use or recommend) start with formulating a plan like "I want a portfolio of 70% stocks and 30% bonds." Refine it a bit: "I want to be diversified internationally, so I want 30% of my stock holdings (approx 20% of total portfolio) to be in non-US stocks." Refine more: "I want to hold an even, market-weighted distribution of US stocks across all cap ranges, but overweight small cap by an extra 10% because I think those stocks will outperform over the long term." Keep refining the plan by adding growth vs value, REITs, TIPS, I bonds, whatever you want until it's as complex as you want to manage. It doesn't have to be perfect; you could easily just stop with "I want X% stocks and Y% bonds."
The sample plan I outlined above says I would need to find separate mutual funds for the broad, total US stock market; US small cap; broad, diversified non-US stocks; and bonds. Now I start shopping for mutual funds at the lowest cost that meet my requirements. These four funds held in the right percentages would be close to ideal: VTSAX, VSIAX, VTIAX, VBMFX.
If I simplify the requirements to just stocks and bonds, then I only need to find two, very simple, very diversified funds (perhaps VTSAX and VBMFX). Or maybe I could use a single target date or other mixed fund that matches my stock/bond allocation.
By the way, this is also how you fight your husband's market timing. If he had a plan like the above, he'd have to explain why this plan he came up with that was supposed to be a long-term, multi-decade strategy, was no longer valid and needed to be scrapped.