She said: When you are praying and you can’t focus, and syaitan keeps on bothering you, then there must be something wrong that you did today. Check back what you did today, where did I go wrong? What sins have I committed? What orders of Allah have I disobeyed? Check, and check again till you find the answer. Open up an account book to check your doings every day. This is what you call muhasabah.
Don't muhasabah just to list down the good deeds that you've done throughout the day, but really really try to search for your mistakes too... you can't afford to continue committing sins. It cost you the 'kekhusyukan' of your solah.. And that is a BIG lost..
So the next time you can't focus in your solah, take some time to recall what you did through out the day. Don't forget to ask Allah for help, ask from Him, may He show you where things went wrong. Insya-Allah.