Striaght away, you cnnot go to parallel code. You need to check is my code optimised? Did I vectorise the code?
REad about profile, see where your code is spending much time. From this try to optimmise the function.
After the above checks are done, then think of parallel code. Every code cannot be parallelised, it depends on how your code is.
Turning on the parallel pool will not run your code in parallel.
