Investors can often make the process more complicated than it needs to be. Trying to time the market and seeking out unproven, unprofitable stocks are just two of the many needless risks you can take to try to bolster your portfolio's returns.

There is an easier path that relies on owning successful businesses over at least several years. Focus on companies that have clear competitive advantages like customer loyalty and pricing power, and you're likely to see excellent returns over long periods.

Three such companies -- Lululemon Athletica (LULU 15.89%), Costco Wholesale (COST 1.05%), and Tractor Supply (TSCO -0.00%) -- look like strong buys right now. Let's look at a few reasons why.

Lululemon

Lululemon recently gave investors some compelling reasons to like this growth stock. Sales jumped 24% in the selling period that ran through late April, management revealed on June 1, despite a pullback in consumer spending in some discretionary niches.

The popular retailer of athletic wear is seeing slower gains in its U.S. stores, sure, but demand soared in its e-commerce segment and in the international business. Wins here helped the company set a new Q2 record, with sales reaching $2 billion.

"Our results reflect the strength of our guest relationships, our innovative products, and how our brand resonates across the globe," CEO Calvin McDonald said in a press release. Investors can benefit from those assets by owning Lululemon's stock, which is up this year but down since early 2022.

Costco

Costco shares are keeping pace with the wider market's rally in 2023, but investors haven't missed their chance with this stock. The big-box retailer's June sales update showed that sales trends are still being pressured by weaker demand for some discretionary niches like home furnishings and jewelry.

The chain is seeing healthy customer traffic across its network, and spending is still much higher overall than it was before the pandemic. Comparable-store sales were up a solid 6% over the past 10 months.

Shareholders can look forward to the positive impact from rising membership fees, which allow Costco to maintain its price leadership position. And with subscriber renewal rates at an all-time high, it's clear that customers are finding plenty of value in their memberships and more reasons to frequent the retailer's warehouses.

Tractor Supply

Investors should take Tractor Supply's recent share-price drop as an opportunity to buy a high-performing business at a discount. Yes, a slow start to the spring selling season pressured sales into early April. Comps rose a lackluster 2% in the period, according to a late April earnings update.

But this retailer of rural lifestyle goods is still forecasting comps growth of between 3.5% and 5.5% this year -- and that follows strong gains in each of the last two fiscal years. Operating profit margin should remain in double-digit territory, helping the rural lifestyle retailer stand apart from rivals like Target and Walmart.

Add in opportunities to expand its store base and broaden the reach of its digital business, and it seems likely that Tractor Supply will be posting much higher annual sales in a few years compared to the $15 billion that Wall Street is expecting it to achieve in 2023.