the following will help get lots of plorts, feed lots of slimes, and earn a good amount of newbucks. im not sure if this will set you back in the long run, it just worked for me as i started playing.
the goal is to set up 2 slime pens for phosphorus largos and 4 gardens with cuberry (the square strawberry looking fruit that grows on trees).
try to put the four gardens together. try to plant them with cuberry, they are found down the road really the only way i could go when i started. if you get to the bridge with the skull and cross bones it was the area just be fore that. if you cant find cuberry no big deal just plant anything in the gardens until you do find some cuberry. grab a bunch of pink slimes and just shoot them out over the gardens. they will eat the food as it grows and pop out pink plots.
the cuberry is important as it will give you double plots from the phosphorus largos. because it is their favorite food.
use the pink plots to upgrade your first pen to high walls, air net, solar shade, and the plort catcher. eventually you will want the autofeeder, i got the music box too but i have no clue if it helps or not. but get your second pen before the autofeeder and music box.
in one pen put a mix of phosphorus slimes and rock slimes. the other pen put phosphorus and cat slimes. if you cant find the phosphorus, they only come out at night but can sometimes be hard to find as they largo into other slimes, just feed the wild phosphorus largos and grab the phosphorus plots, they can be used to make the phosphorus largos. i found 10 largos in the pen work nice, more might work better.
dont forget to upgrade your gardens. im not sure scareslime even does anything, the loose pink slimes kept eating my stuff until i got rid of them even with the scareslime.
be careful with the largos getting a 3rd type of plort and becoming tar. other than that it should be super easy.