Change you water frequently and don't over do any soap or cleaner you put in the water. I use plain water on mine and change it as soon as it starts getting cloudy. I also rinse with vinegar water to cut soapy residual if I do add any soap to the water, the vinegar will cut the soap if you rinse with it.
I've seen articles that recommend windex window cleaner for that (and it works). The ingredient that makes it work is the ammonia in the windex. Instead of buying window cleaner, which isn't cheap, use ammonia or vinegar. I also have used a steam mop after cleaning to remove any missed dirt or residue.
Change you water frequently and don't over do any soap or cleaner you put in the water. I use plain water on mine and change it as soon as it starts getting cloudy. I also rinse with vinegar water to cut soapy residual if I do add any soap to the water, the vinegar will cut the soap if you rinse with it.
If it had a shine originally and not now I guess wear is the problem and you would need a polish for ceramic tile or clean tile with vinegar water and then mop with club sodahttps://homeguides.sfgate.com/polish-ceramic-tile-43635.html
I've seen articles that recommend windex window cleaner for that (and it works). The ingredient that makes it work is the ammonia in the windex. Instead of buying window cleaner, which isn't cheap, use ammonia or vinegar. I also have used a steam mop after cleaning to remove any missed dirt or residue.