Keeping porcelain tile lean

I had some porcelain tile laid recently, but after I mopped it with water, it looked awful and left streaks everywhere. What is the best way to keep it clean, and what product should I use.

No one here can answer that!

Clean water and mop is a must of course. The degree of contamination on the floor when the cleaning begins is a consideration. The type of cleaner being used may promote an undesireable result if the the cleaner isn't fully neutralized after its use.