I have found that patience is a virtue with Sims Free Play, so if you are playing with the same mindset that you play The Sims 3 or any of the other Sims games, you are not going to be happy. If you have zero life points it's more than likely you are using them to complete tasks faster. Don't do that. You'll want to save your lifepoints for more important things such as completeing buildings faster, but even that isn't necessary.
I did use the time cheat for awhile until I figured out that I was doing myself out of some simoleans. For example, the starter house gives 5 simoleans every 5 seconds. Do the math. It earns you 300 simoleans per hour. That's not including the dog that digs up treasure for you. That dog can give you anywhere from 1 simolean to 100 simoleans and the occasional life point. Taking your Sim for a ride in the car is also a good idea. You make money by tapping on the musical notes and it's a 3 minute ride. Not a whole lot of money, but every little bit helps.
Other bit of advice...planting pays better than baking, but when you have accumulated enough Sims, use your unemployed Sims to plant the longer lasting crops and the employed ones to plant the shorter term crops. The best one for the long crop so far is green beans. The best ones for the short crop are corn, watermelon and potatoes, with potatoes paying out the most. Those are just the levels I've played. The other levels yield plants but some of them cost life points and are long point, and some of them are just long term crops; it's a good idea for you to pay attention to the price/profit ratio of the crops.
For businesses, I build the car dealership first (free Prius!) and then the hobby shop and the pet store. For work, Firehouse and Scienc lab first.
It doesn't hurt to let the game run on it's own time and spend the time either clicking on the starter house with the dog, or have your Sims drive around in their free new cars...all it takes is patience and you will slowly but surely make money. Also, don't buy anything unless you have a goal to buy it. That gains you simoleans and sometimes life points.