Everything depends on on several factors in gambling to put your ticket in that winning slot. From time, to your stake, to the odds and to how frequent other gamblers have won for the time, day/week.
I would like to add some reservations here that this describes casino games and not sports betting since the degree of wins obtainable from other gamblers has nothing to do with your sports booking, the outcome of every match is entirely dependent on the actions on the pitch.
Although there are some correct factors you mentioned that applies to sports betting too which is your stake, the odds present and also I'll add the good predictions you make out of your good understanding of the both parties involved in the match, but for the results, you rely on the outcomes after the conclusion of the matches.
Sports prediction is quite a near independent area of betting in the sense that most times when you book your tickets, you tend to know when you're going beyond possible lucks. Factors like odds are always there which is the first step in making a booking decision. Practically speaking, a generally assumed better teams are given lower odds, but sometimes it doesn't go as predicted. I believe that to succeed, you have to be current with teams actions and injuries update in order not to play based on your previous knowledge of the team even when the key players are not available. Your stake also matters, lower stakers mostly book longer tickets which opens them to higher chances of loosing than winning. There are lucks more in casinos whose principles are not very clear, but sports betting is more tactical.