To harvest crops: Go to the market, click on someones avatar, click the hire them feature. You will make more money on your crops. (Don't do this unless you have crops ready to be harvested or the people are mean about it.)
To harvest someone else's crops and make money: go to the market and beg for a job. (Ok, some people don't like begging.) If you just hang out you can sometimes just get jobs.
When you are hired click the Yes, I want to make money feature and it will automatically take you to their farm to work. Once you are at their farm highlight the crops that are done and click on them...then go as fast as you can from patch to patch.
If you harvest your own crops you do not make as much money as you would if you hire someone else.
The more you buy (especially big ticket items) the more your experience points go up the quicker you can get more land and buildings.
Plant your crops close together so you can make lots of money! Use the wrench at the top right and remove space between the fields.
Do not plant grapes after 7 or 8 PM at night or they will be dead by morning!! And you will lose them all!
Does that help a little?