The first thing to do when getting started with Farming Simulator 25 is to complete the tutorial. It is always very tempting to skip the tutorial in any video game, and especially if you have played previous games in the series, but I would always recommend playing the tutorial in full to get to know any changes from previous games or pick up any hints.
Secondly don’t rush to buy the biggest, most powerful machinery straight away, you would be surprised what you can achieve with the smaller stuff.
Start with cereal crops before you try your hand at anything more complex.
If you do find yourself low on money, you can always take a break from farming and go looking for collectibles. You get a monetary bonus for each one you collect and the entire map is unlocked from the start.