I know that for my investor (buy and hold) buyers, it's just a matter of persisting. We've had really good luck pursuing properties that have some type of contingency that is hard for the typical buyer.
For example, on one property, the seller needed extreme flexibility with the close date--faster is not always better by the way--so that they could have time to find their next property. They also wanted a longer lease back period. That worked fine for my buyers (who always use mortgages) and we were able to get the property even though they weren't the highest offer.
We make many offers before one gets accepted and are frequently competing with up to 20 other offers. Persistence pays and so does keeping an eye out for that seller with conditions difficult for the typical buyer.
p.s.--My buyers typically never waive the inspection objection and will sometimes waive the appraisal objection. It's possible to win the deal even with longer closing times, a mortgage involved, and contingencies even in a hot market like ours.