Guitar picks are the instruments themselves, and it's important to know what you're getting before you buy. A guitar pick is an instrument-specific plectrum utilized for playing guitars. Picks are usually made from one solid material, usually of rubber, plastic, wood, felt, or tortoise shell. They're frequently shaped in a shallow isosceles triangle with both the equal sides rounded and the other edge less round.
The earliest guitar picks were made with nails or a piece of cut string to push down on the strings; today's versions are made with steel or aluminum alloy picks. Some players favor the flat-tipped variety, which allows a more fluid playing style and is easier to control when playing faster passages. But flat-tipped guitar picks also allow the guitar to sound like it's being hit directly by the player's fingers rather than being subject to a rolling sound caused by the fingers rolling over the strings.
Guitarists who perform string skipping (fretless picking) typically favor flat guitar picks. While flat-tipped plectrums are excellent for string skipping because they give the instrument a smoother tone, some flat-pickers are poorly suited to strumming because their flat tips can cause the guitar to sound thin when it's played rapidly. Fingerpicking (fretless picking) players sometimes use open-back plectrums, which are made of a flexible piece of metal covered in felt or rubber. These plectrums are usually used for lead guitar and classic rhythm guitar. Open-back plectrums are very comfortable for fingerpicking players because they don't trap feedback or noise from the fingers causing unwanted "mic feedback"; they're also perfect for solo playing.
One important distinction between plectrums and finger picks is the distance from the fretboard. In general, finger picks are closer to the fretboard than plectrums are. So when selecting guitar picks, whether you're working with a flat pick, an index finger pick, or a thumb pick - make sure you know how far away from the board your plectrum is! If you have never used a guitar pick before, or you're uncertain about which one to buy, there are a few quick tips that can help:
There are three kinds of guitar picks that you will encounter when shopping for guitar picks. The first kind is the bridge pick, which is not technically part of the guitar picks category. Bridge picks are typically recommended for a beginner guitar player because they are easy to control. A bridge pick is recommended primarily because its action is easy for a novice to master, making it ideal for the beginning guitar player.
The second type of guitar picks is the thumb pick, which is the pick most commonly associated with professional guitar players. (Thumb picks are also called "thumb trainers" or "thumb breakers.") While they do have a tendency to take up more space on your hand, thumb picks are highly recommended by many experienced guitarists and musicians.
Next are flat picks and thumb picks. These two types of picks come in different sizes. Flat picks are typically used on acoustic guitars, while thumb picks are better for lead/progressive guitars. While flat picks are less likely to change the pitch of a string than a thumb pick, using one will require a bit more practice and accuracy. Also, while thumb picks do have the advantage of easier tracking, they don't play as deep as a flat pick does, and their action is also a bit less consistent.
Finally, there are plectraps. Plectrars come in a wide array of sizes, shapes, materials, and prices. Like most guitar picks, plectraps should be taken slowly and thoughtfully. One should not make the mistake of choosing a cheap plectra because it might have the wrong shape, which could lead to inconsistent tuning.