Ideally, google maps will help you to reach this place. Google navigation is accurate to Thottikallu Falls.
However, below is a brief route map to reach your destination:
If you are driving your vehicle then from Bangalore take the Mysore Road, and enter the NICE Bangalore Mysore Expressway. You will get a Toll Road called the NICE Ring Road from where you need to take the Kanakpura exit to the Kanakpura road. Turn left from the Saaluhunase Bus Stop and continue on the path until Gulakamale Lake. After this lake, you need to turn left and stay on the curved road until you spot the TK Falls Parking Area.
If you are to take the bus route, you have to board a bus from Banashankari Bus Station. From Kaggalipura Bus Stop, the bus makes a left, and you will have to get down at Nallakkana Doddy Bus Stop. From here, Thottikallu Falls is at a walking distance. Or you can also board a local bus from Majestic Bus Stand. It is an hour journey from Kempegowda Bus Terminal. If you are looking for accommodation, you will find many options situated close to the falls.