Decide if the floor needs to be refinished.
A finish on hardwood floors does not last forever. It may be that your floors need to be refinished. You can extend the life of a floor finish by making a no shoe policy, clipping pet nails, and using furniture protectors. Even with these precautions, eventually a hardwood floor will need to be refinished. If droplets of water bead up on the most worn parts of your floor, then your finish is likely intact. If, however, droplets of water soak into the floor turning it white or grey, your finish needs some attention.
Check for wax buildup. If you regularly use a wax on your floor, it may neep to be stripped off. Waxing over time dulls the finish of your floor. Waxing should only be done twice a year, but a lot of people end up doing it more often. There are commercially available products that can help you remove the wax buildup from your floor.
Make sure you aren't mopping a dirty floor.
Before you attempt to use any type of a wet mop on a hardwood floor, the floor needs to be thoroughly swept or vacuumed. Leaving dirt and particles on the floor to be mixed around with a wet mop will leave streaks, scratches, and residue on the floor. A thorough sweeping and vacuum job is necessary to a shiny end result. If you do decide to sweep, use a dust mop to avoid scratching your floor with a broom.
Experiment to find the right products for your floor type.
There are a lot of products that market themselves as hardwood floor cleaners, but don't measure up. A good place to start is finding out what your floor manufacturer recommends. Be warned that what they recommend may be made and sold by them. It will, however, give you a good idea of the type of product you should be looking at. No, you are not doomed to buy expensive hardwood floor cleaner for the rest of your life, but it may take a little experimenting to find a cleaner that leaves the wood the way you want it to look.
Don't be tempted to use too much cleaner to achieve shine. Knowing how much of any cleaner to use is an important skill. It's tempting to add a lot to get the desired results, but in most cases, this doesn't work out. Remember more soap does not equal more clean. Floor cleaner is rarely used liberally. Instead it is used sparingly. This is especially important for hardwood floors that can become damaged when over wet. Use products and water sparingly. Wipe up spills right away. Protect the floors and they will keep their beauty.
Be sure to buff hardwood floors dry. One other trick that can help restore shine to your hardwood floors is to buff them after they've been mopped. One friend swears by clean cloth diapers to buff her floors to a shine. Others use microfiber cloths or flat mop heads to get the job done. Failing to buff a drying floor is like begging for streaks that will keep your floor from looking shiny. Take the time to buff the floor dry and enjoy the shine.