Try the blog The Girl Who Games. She gives great tips on how to quickly make money and build LP. Everything she suggests is appropriate and you won't be cheating.
When you tap on the task list, see if you have a flashing icon in the upper lefthand corner of the screen, kinda looks like video reels. Tap on that and watch the commercials, usually 20-30 seconds each. Earn 2 LP, 1SP, and over 8000 simoleons each day. The daily reward goes up as you increase town value, be sure to collect every 24 hours.
The cooking hobby is the fastest hobby to complete and pays 5 LP. It's good to have a couple of sims devoted to this. The 2nd best, to me, is the fishing hobby.
For me the fastest hobby to complete is ghost hunting because you can start it every 3 minutes to get a new item. So even though you need 18 items to get the 5 LPs this is still the fastest.
But it all depends on how often you enter the game and for how long each time. Choosing the fastest hobby doesn't really matter anyway because you need to do them all and this will always give you more LPs than you need to stop all you sims from any unwanted aging.
Comments
The cooking hobby is the fastest hobby to complete and pays 5 LP. It's good to have a couple of sims devoted to this. The 2nd best, to me, is the fishing hobby.
But it all depends on how often you enter the game and for how long each time. Choosing the fastest hobby doesn't really matter anyway because you need to do them all and this will always give you more LPs than you need to stop all you sims from any unwanted aging.