Some of these tips are obvious.. lol. ^^ I tried my best!! <(0.0)>
My first tip on saving time, is take advantage of your chicken coop shipping bin! When I started playing I had no money, so of course I went to the mountain tops & fields to gather wild grass. Well, because the time is so short, instead of walking up to the main shipping bin to empty my rucksack, save yourself 10-20 minutes and go to the coop shipping bin It's much closer to the South exit.. Plus, all time stops when you go inside a building.
After that, I would go about my business in town, and then at the end of the day I would save about 3 to 4 hours to work on my field. Every day you'll get new weeds, so If you clear little by little you won't have a weed mess. Also, MAKE SURE you go to the beach and take advantage of all the wild grass. You can easily get 800 coins or more just from picking up grass (depending on the season, exuding winter)
Here are places where I find the grass-again depending on season the amount varies.
Outside of Gotz place. (About 2)
By the mountains (It varies)
The beach (around 4 depending on season.)
Carters Graveyard (1)
By the spring mine (spa area) (About 2-3)
And that's where I usually get my grass. If you want to befriend Mary (Grays rival) then I suggest giving one or more a day to her, and talking to her twice afterwords. Also, the doctor loves them. Some people you shouldn't give it to are Popouri,Gray,Cliff, Ann,Rick ect.
Last quick tip: When buying chickens or sheep or cows, make a fence for your chickens and plant some grass. You won't need to buy chicken feed (Except on those rainy days) So keep like 20 bushels. For sheep just leave them outside all day, as they'll want to walk around and are easier (BUT SLOWER) to put back. Again, keep some for a rainy day. Same goes with cows. Just make sure w/ your chicken that you take them in before 8pm because there's a creepy wild dog thing that comes and tries to eat your chicken!
I hope I helped a little. ^^
Feel free to comment, add, or correct any tips you see. CORRECTION IS CRITICAL! lol ^___^