A well-crafted watchlist is critical to smart investing: It can help you find attractive buying opportunities, and it can save you from rushed, emotional decisions by slowing down the process. The Fool now offers MyWatchlist.com, your free, customized hub to follow the performance and Fool news and commentary about the companies you're watching.

But what to put on your watchlist? In today's entry in our ongoing series, Motley Fool Stock Advisor analyst Jason Moser shares three companies that he's added to his watchlist, and one that got away.

One to watch
Nestled comfortably in the middle of the financial relationship between a university and its students, Higher One Holdings (NYSE: ONE) just wants to make everyone's lives a little easier. It will help the school manage its financial aid disbursements and refunds, it sets up debit cards and checking services for students, and it will even allow its Higher One-branded debit card to double as a student ID. By charging a fee on each side -- to the universities and colleges, to the bank whose services it offers, and to the students on each debit-card transaction -- Higher One has planted itself in the sweet spot.

While Jason is intrigued, he's waiting for the company to develop more of a track record as a publicly traded company. With an IPO earlier this year, the founders had their second earnings call ever earlier this month. And while the company seems to be on the right track, it's worth watching and waiting for a while before making a buy.

Two to watch
In the same way that universities might not want to deal with sending out financial aid checks to its students, nursing homes, hospitals, and rehab centers might be more comfortable having someone also provide the food and do the laundry. Healthcare Services Group (Nasdaq: HCSG) has the experience and the economies of scale that allow it to offer housekeeping, laundry, linen, facility maintenance, and food services to health-care providers more efficiently and cost-effectively than they could do it themselves.

The share price has run up lately, but Jason's optimistic he'll see another buying opportunity soon. When he does, he'll jump in, because you can't go wrong betting that people will continue to get sick.

Three to watch
A member of the PGA for three years, Jason is a discriminating golf consumer. But when he or his daughters need clubs, gloves, tees, or other accoutrements, he heads not to the local pro shop but to Dick's Sporting Goods (NYSE: DKS). The national specialty sports retailer knows its stuff, stocking its in-store golf shop with high-quality equipment and PGA-trained professionals, for example. And the store is poised for "tremendous top-line growth," says Jason. Dick's has over 400 stores now, and management sees the opportunity to double that or more.

But the stock price isn't cheap, hovering above $30 per share. If it dips down to $25, Jason plans to back up the truck. And even if the stock price stays where it is, he's very tempted.

And one that got away
Hopefully, Jason won't wait too long to pull the trigger on a long-term winner. He spotted Air Methods (Nasdaq: AIRM) when it was at $36, and now the operator of ambulances in the sky has flown to more than $42. The company, which owns and outfits the helicopters involved in air medical emergency transport, remains a favorite of Jason's, but it's elevated well beyond his comfort zone.

And that's exactly why it pays to watch. You can make smarter investing decisions with your own version of My Watchlist, new and free from the Fool. Click below to start following one of the stocks mentioned above:

Roger Friedman doesn't own shares of any companies mentioned, but they're all now on his watchlist. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.