If you can grind in the coli during fests, you can get a ton of currency and use it to buy as many of the fest items as possible. Use intuition to guess which ones people will be most interested. Some of the really good stuff doesn't even take a month to hit 100g+ in price.

You can usually buy fest skins and resell for a profit, although they usually sell pretty slowly so some patience is needed. Most of the coli chest ones won't be popular, but there have been a few exceptions. And if you're lazy to buy the lot, some intuition/guesswork can usually lead you to the ones that people will be crazy for in a few months.

If you have time to work on any type of creative endeavour and sell your services on FR, do it! Even if you think you're not particularly good or you're only capable of doing something really specific. Don't give up if you don't get customers at first. And even if it doesn't work out, you haven't wasted any time, and if it does, you've made money.

Also, resell UMs. I know it's pretty frowned upon, but use some common sense and courtesy. Don't sell right away, and don't keep targeting the same creators. Check out all the threads you can - there's often hidden gems that go for big bucks months later.

Try to make sure Baldwin is constantly working for you. That guy's basically free money.