Offside betting is the part of the stats forecasting (like the corner kicks forecasting). One can make a bet on the offside is available in a little number of bookmakers and only for the top matches. But it makes it even more interesting!
To begin with, start looking for forwards who often are on the edge of the offside. There is a pretty large number of them, and they don’t change their style when transferring to the other club. They are usually quick and slick, though there are exceptions. If such a player is in the first team, it usually adds at least one offside more at the end of the match.
Of course, you will have to study the tactics and the style of the team (if there are) and the coach.
Moving from the defense to the attack. A long pass, as a mean of getting out of the defense increases chances for the frequent offsides. Give and Go is precisely what you are looking for.
Pay attention to 4 defenders. If they are perfectly coordinated, it makes it easier for them to catch a rival into the offside trap.
A bad or missed attack is a good base for the offsides. If the attacking half-backs and the forwarders don’t understand each other, the offsides will be frequent.
If possible, find out the stats of the fixed offsides among the arbiters. Many of them are overcautious, so track them down. Another important condition is the odds. Often the bookmakers let you stake on the offsides, but the margin is high. If you notice that it is too high, better do not bet. This is the other advantage of betting over the office job: you are free to make the final decision.