i made a bell making guide (
link) a bit ago and it still works for me. i consider these to be lazy ways of making money, so if youre looking for big bucks quick this may not be it. if ur a patient person, if u save the bugs & fish from these methods for flick or cj respectively you'll gain more than what ull get at nook's cranny. a tip i forgot to put in there is that for fish i sell everything and dont let any go but for bugs, since u can see what ur catching i dont release anything because i only go after what will get me bells.
i found that bell trees are also a good way of making money. apparently a reddit user (
link) found out that you can plant 10k bells on one day (so when fully grown will give 30k) and then 99k the next (when fully grown will give 297k). so you could get 297k bells every other day. ive been trying to do this since ive found out about it, but it's taking me a while. i messed up on my tracking of this so i've restarted for april.
basically what i have been doing with this is every day when i plant a bell tree i write the date i planted it, and the amount i planted. since i don't care if i've lost 3k bells, i plant 11k bells everyday. when the tree fully grows in four days later, i go back to where i wrote the date & how much ive planted and i write when i shook the tree, and how much i made from it. for example, if i made 33k bells on april 1st but only 30k on april 2nd then i know i should plant 99k bell trees on the odd days of april while i plant 10k bells on the even days. of course, this will change next month; i may have to plant 99k bells on even days and then 10k bells on odd days, but since im keeping a log i'll cross that bridge when i get there (not gonna lie, i literally bought a planner to track turnip prices & bell trees).
the only other ways i can think of gaining money is selling fruit, crafting basic things (like fruit items, weed items, maybe even softwood items (too much softwood)) and selling them for a bit of profit. i wouldnt do anything with the egg/easter event things now because u can eat ur eggs!! which will give u the food buff, which is good for when ur needing to move around trees since they stack up to 30 compared to fruit's stack of 10. u can also keep the eggs & extra recipes around for when the event is over because some people may not have gotten to play the event, so u can give it to them (or sell it). u could also try to get a lot of materials and sell them, but i dont think it'll sell for much for the amount of work you put in. and like others have said, selling nook miles tickets.