The main simplify function is full of heuristics and is itself a basket of more specialised simplify functions. One thing to try one or several of these specialised functions.
Another tip I don't think gets mentioned enough, try to provide domain information for your symbolic variables. By default all these systems assume the most general solution. But if you know x is a positive real value, you should tell that to SymPy.
Anyone has tips to reduce time required to simplify?