First thing you might want to do is to get more allies. The more allies you make the more help you can get and progress. Once you leveled up to, example level 5, recruit 3 workers and give them equal points.
When you earned enough money, go upgrade your clothes by clicking the magazine on your desk. Doing thins will increase defense. You may also want to purchase some power ups; its like the relic slots in Ninja Warz. Now, to level up faster you can fight the lower levels by going to the 'fight' door. Heal yourself using the first aid kit after fighting. You can also level faster by fighting high level but ONLY fight human players. You can easily beat them if you got an Easy Button power up which you can get from 'gifts'.
Here are some useful videos about leveling fast in Office Wars. No cheats yet though. But let's wait and see if there will be some sort a kind that will surface.
We'll update this for the Office Wars Cheats or Hacks. We're still looking around.