Things You Need
to set up your system quickly and easily
— What do I need to mount the cartridge correctly?
— First and most importantly, some free time. This is not the job to do under pressure or stress. You would also need some hardware and tools:

  • If you bought your cartridge new, it should include the mounting screws and nuts. If not, make sure you have them
  • Non-magnetic screwdriver. Some cartridges (usually of the moving coil type) have pretty strong magnets in them. If you use the regular screwdriver, it can take the cantilever right off before you realize what's happening!
  • Thin nose miniature pliers to attach the wires to the cartridge. Do not use the tweezers for that — tweezers slip and can easily damage the wires or the cartridge itself
  • A specialized scale to set the downforce (see next question)
  • Plenty of light
— Which downforce scale is the best? How about Shure's? Ortofon's?
— The simple mechanical scales of the kind Shure and Ortofon used to make are not very good. Shure's can damage your moving coil cartridge — it's made from magnetic material! The precision offered by these scales is not enough for today's cartridges.
— There are many types of noname electronic scales for sale at Amazon, Aliexpress etc. Most are quite good. But before using them, it pays to check that the pad of the scale is not magnetic!
— The expensive name brand downforce scales have no advantage over the basic ones
Pretty but dangerous
Ugly and effective
— Which alignment protractor should I use?
— The right position for your stylus is determined by the tonearm's geometry. If in doubt, you should always use the protractor that came with (or is suitable for) your tonearm.

If you change cartridges often, or mount tonearms yourself, I recommend Dr. Feickert Protractor NG. It is very well thought out and easy to use.
— Should I get a test LP? Which one is best?
— A quality test LP can assist in setting the antiskating right.

Strictly speaking, it's not absolutely necessary. Antiskating is an approximate setting that doesn't need to be "dialled in" exactly. But, unfortunately, the antiskating scale on the tonearm can not always be trusted. In my personal opinion, knowing your antiskating is set right is worth the price of a test LP.

Any unplayed brand new test LP that has antiskating setup tracks is fine. Do not buy used test LPs — you never know if the tracks you need are still useable. The three most popular test records are The Ortofon Test Record, Hi-Fi News Analogue Test LP and Analogue Productions test LP.

Please do not use a test LP to set anything up except the antiskating (and the turntable speed if you must). The setup methods offered by the test LP manufacturers are often questionable, and the quality of the signal tracks on the discs varies. It does not matter much for antiskating, but for azimuth you can get very far out of alignment if you follow the test LP instructions.