I guess a lot of us got to a similar result taking different routes lol
Breeding Barn - Do you have enough money in the bank to invest in your barn and have a comfortable amount left over?
Make sure your bank is very healthy and skip the 2yo auctions at the start of the season and focus on buying a proven horse at the mid week auctions. Something that has won Group or Graded races and is young. If it is young you can race it for a few seasons and pick up good prize money and then send it to stud.
Wait til you have a really healthy bank before buying the most expensive 2yo's. Buying cheap 2yo's isn't worth it unless you have a cheap stallion and five or more mares and you sell all their foals as a way to build your bank.
5 - This will start debate lol but while you are early in your career - if you have a horse that wins a lot of prize money, I say keep racing it as building up your bank is more important at this stage. Once you have plenty of money then you can start to shorten their careers.