Steel tip darts are the darts used since the game was invented and what the big money professional darts players' use. Notwithstanding the amazing advances of the soft tip darts world, the steel tip darts are still the darts used in all the major competitions. There is some argument between steel tip darters and soft tip darters as to whether the soft tip game is a "proper" game of darts. However the automatic scoring and the safer soft tips of the electronic game make it popular with home users.
As the name suggests the tips of steel tip darts are steel with a sharpened point so they can stick into sisal or paper or even a wooden dart board. The steel tip has had some innovations over the years, like the Bottelsen No Bounce out darts that had the trademark Hammerhead system in the grip whereby the tip can retract slightly into the body of the dart absorbing the sharp impact if a dart hit the wire or staple on the dartboard allowing the forward momentum to push the dart past the obstacle and stick into the board.
Black widow darts had a similar system called a movable point that also had the added advantage of allowing the body of the dart to swivel around the tip achieving the same effect as spinning shafts i.e. if an incoming dart strikes the flight of a black widow dart already in the board, the flight can spin out of the way minimising the deflection of the incoming dart.
Another step forward for darts is the metal used to make the darts today. Tungsten has all but taken over as the material of choice for the body of the dart, with its superior density to traditional brass, the same weight of dart can be made much thinner, increasing the chances of getting three in a bed and that 180 score.
The tips are obviously different for the two types of dart, but the other parts like the shaft, flights etc are the same. The weight of the darts is the other difference. With steel tip darts you can go all the way to 50 gm if you want, whereas soft tip darts have a 20 gm limit normally, to stop the dart damaging the electronics.
As for maintenance of your steel tips, be sure to keep the point sharp, either by rubbing the tip on some grinding paper or using the shaped carborundum stone you can get specifically to keep steel tips sharp. If you want to spend the money, there are motorised sharpeners that will sharpen your dart at just the right point angle.