Without status or money, it's more about flexibility. Flexible in when you go and where you go. Like others said, mid week, off season. For example, trying to upgrade a flight to europe over the summer is fairly difficult even for people with high status. With most US airlines, you can cancel and still get the credit without paying a change fee. So if you must fly business, you can cancel at the last minute and try again on a different date and keep trying. On UA, for europe, I've noticed more advanced availability on return flights to the US. So if you are ok with one way only, do that. Also, check other airlines, you may find a lower price and higher quality. Unfortunately, if it were easy to upgrade, everyone would be doing it. There isn't any magic trick unfortunately.