Something that I remembered from the pc one that works with this one. With shops and game stalls, if you put a path directly behind them you'll find that visitors that walk behind them can actually purchase and play from them, thus increasing customers.
As for staff, you can only assign with the cleaners (tap on worker, tap on edit and tap on the brush next to the pick up icon, then click on the path)
Bins...there are no bins! You'll just have to have more workers and make sure that they are assigned to there own zone. To stop people throwing up everywhere after a ride simply place a toilet near by. Coffee shops do have their own bins though.
Oh yeah the stall thing at the front of the park thing does work, make sure they are all in front of the park, so remember to make sure you reserve some space for shops you get later on. Also make the prize around $600 and the win rate around 20%, people will spend their cash on them first before going to rides. Stick all of the big rides near the back of the park and make sure the are way behind the stalls otherwise people will see them and wont spend cash.
Another thing to do is hiring and firing your workers on a constant basis! For some reason this keeps there wages down and the fresher the worker the better he works.