At the beginning of the game, it always took me a while, to get enough money for the newest machines and/or animals.
What gave me a boost was planting bushes/trees and selling the fruits, mostly they were taken for full price really fast. Sometimes I sold the apples for a little less, because I didn't have many stalls when at that level and needed the stalls to free quickly again.
After a while I hired Tom to get saws and axes, because I didn't really think of the mess the bushes would produce :D
So far I hired Tom twice (3 times including his trial run, but I didn't use him properly then), for saws and axes and for saws/explosives. Things you can't produce yourself. Others suggested to let him get the most expansive items and sell them at the shop. With your amount of diamionds, this is a good option also!
The rest of my money I made by buying cheap stuff from the paper and reselling it, sometimes you buy for 30 and can resell for 100. It takes time though, and luck. And you have to know, which prices are good and which items will sell afterwards (good: cheese, anything including or being sugar, bad: anything with ham/bacon).
Also at your level/situation, sell all the expansion stuff! You need the money and barn space more. Try this forum for trading building materials or just sell them when you have too many. Expansion will come 'naturally' later. Those materials always sell for full price real quick.
Don't focus too much on other's boat, it gives experience, but half the money compared to the road shop. Do it from time to time or with items that are not selling great at the shop.
And maybe you should play it a bit more patiently.
"I've spent the entire day making and trying to sell road side to make enough money for juicer."
This is no race, when you know, there will be a new machine coming with the next level(s), start saving up a little before that. Maybe three or for days earlier. Then it will be easy.
I never bought diamonds so far, and I am glad the game is so fair to be well playable without doing so. From leveling up and the challenges, I have around 70 at the moment and will use them in the near future to get more production lines in the machines, which is very convenient. I wouldn't recommend using them to speed up any processes, rather suggest more patience there.
Just my 5 cents, most important: farm as it is fun to you! But at the moment you don't seem to be satisfied!
P.S. send this as a pm also, since he doesn't seem to be a regular (yet)