For me, the question isn't how the make the most money in the shortest amount of time. Instead, it's how to make the most money while still having fun. As of this current iteration of GT7, I've come up with the following ideas:
-Only set the difficulty to normal. There's no reason to set it to hard, not even for bragging rights. I've found the Gr.1 Prototype Series races to be impossible to win on hard, so I brought the difficulty down to normal. The real challenge, I'd say, is in Sport Mode, whether it's trying to get a good qualifying time for the Daily Races, entering championships, raising your DR/SR by performing well, or in my case, seeing how many Daily Races I can do where I come in the top five.
-Speaking of Sport Mode, I also enjoy doing the online time trials. Ever since they've introduced rewards to them, I've never scored a bronze - only silver, with the exception of a single gold.
-Set a budget. I know this sounds silly for a videogame, but it's a profoundly valuable skill in real life, too. So for me, this means not immediately buying cars from the UCD/LCD that only come in a single paint scheme, like the Ferrari 330 P4 or the Porsche 550 Spyder, as they'll eventually be back with that same paint scheme. But I do have credits set aside for cars that may show up in the UCD/LCD in colors that I really want, as I personally prefer to avoid repainting most cars. Notable recent examples from the UCD alone include a Toyota Sprinter Trueno (AE86) in High Tech Two-Tone, a Nissan Skyline (R33) GT-R in Midnight Purple, and a Honda NSX Type R '92 in Championship White. So far, I've seldom gone below 10m credits, though I'd ideally like to get to 20m again, since I'd like to buy a second McLaren F1. I bought my first one in Base Silver, so I'd like my second to be in Historic Orange; I'll leave one as stock - barring the purchase of some tire compounds - and modify the other, including the installation of a widebody. But I digress - I'd also recommend only buying cars that are absolutely necessary to enter certain events, as I'm typically able to simply rent cars in the overwhelming majority of Sport Mode events, with very rare exceptions like the BMW M3 (E46) event at Alsace - Village, or the FR race at Monza.
-Most importantly, look forward to future events being added to World Circuits, additional seasonal events being added (as PD mentioned this past spring), and of course, the ability to sell cars. That last feature is something I'm hoping won't be a basic as it's been in previous GT games, as I'm hoping it could be a fun activity in its own right. Heck, I'm also hoping we'll be able to sell parts, too.
