After unlocking the cheat Llama you can do many other cool things, e.g. the mailbox cheat and teleportation without a teleport machine, but one thing I have found is this...

When your sim is at work hold LT then click on the building they work at, it will say Force Opportunity, Force Event and Force all Events.

Use these to give you a job boost.

PS: For some reason if you are in the medical career on first promotion level it fires you because some events can be bad.