As a beginner you should listen closely to the work of your idol. Of course, at first you will be just in awe, but remember that even those heroes once started from scratch. Maybe their possibilities were even more limited than yours because nowadays you can easily get a decent-sounding instrument for relatively little money while in the past it was an exception for somebody to have a reasonable instrument from the outset. Dare to have a look at the jazz-department too as bass players within this genre are true masters with a double bass.
It is your part to support the groove of the whole band right from the beginning. This creates the collective feeling of a tune; the togetherness in feel and sound. A common mistake of beginners is that they focus too much on themselves and the notes they play.
Listen to what the other musicians are playing - especially the drummer. You'll need to follow the drum-pattern closely, so try to figure out exactly what the kick drum is doing. For most types of rhythm the bass drum counts on the one and accordingly, the stressed bass note should occur here as well. By and by, you will improve your technique and therefore be able to move more freely around the root note. Always keep one ear on the drummer, however. It is okay to take minor excursions on your fretboard as long as they end up in line again.
As a bass player you should know about scales and chords and it is here you will find the proper notes for your bass runs. A famous bass player once said in an interview that the most important thing is to be able to recognize the root notes of the chords in a bass pattern. Of course, you can do really wild stuff on a bass guitar, but I think that the bass is primarily designed to be the link between the different instruments in a band.
Using a pick
On the bass we distinguish between three different ways of picking the strings. Using a pick is common for beginners and there are special bass picks of convenient size and robustness. Some are thick and firm for a crisp attack, others are soft and flexible for a rounder and richer sound. Playing the bass with a pick is practiced and handled in the same way as on a guitar. Practice both down and upstrokes equally.
Another alternative is using the fingers to pick the strings. This technique doesn't refer to any classical style - it represents the way of the professional rocker. If you take a look at The Who's video of their rock opera, Tommy taken in the summer of '89, you will see a perfect example of John Entwistle's masterly finger picking technique. Now, that's how you want to play the bass, isn't it. Who knows, maybe you have the power to learn playing it that way!
Bass finger picking is achieved slightly differently to guitar finger picking. The thumb will basically reinforce the picking hand. Most bass players use only the index and middle finger to achieve a consistent double strike. You'll have to try these things out for yourself in order to develop a proper finger picking technique.
Slapping is a common technique as well. Suddenly, the thumb becomes a very busy fellow as it is slammed into the string producing a very dry and punchy sound. This technique is used for downright funky rock and allows you to reach an incredibly high speed on your riffs. The only thing here is that you need to hit the string precisely at the right point. The player can add some interesting accents by pulling a higher string on the off-beat with the middle finger - at an octave to the thumb-slapped note, for example.
Of course you can also combine all these techniques in order to achieve a larger repertoire. As a matter of fact, you can't come up with slapping on each and every tune because at some point it starts to get really annoying. Slow blues tunes or ballads require a restrained yet enriching way of playing. It wouldn't go amiss to have different techniques up your sleeve to surprise your band mates with.
Fret finger technique is a very individual matter. Purists will advise you to develop an accurate technique using all four fingers of the fretting hand while the thumb stays hidden behind the neck as a reinforcement. The fretting fingers are placed on the fretboard at a perpendicular angle.
In practice, things are often slightly different - even in the pro's department. The little finger is hardly ever used as a fret finger here. The perpendicular fingering is also often disregarded in order to save space on the fretboard. The entire fret hand lies flat on the fretboard, which enables the player to immediately reach four notes in a single fret, either simultaneously or one after another. Single fingers come into play only when lower notes than the ones beneath the flat hand are to be played. This technique lets you control the length of a ringing tone as well.
It is always advisable to learn a proper academic playing technique, though, of course, your own way could result in interesting innovations as well.
But what does a bass player practice in his room at home? First of all, scales of all types; the information given in the guitar section might help you here though it depends on your favourite musical style what you play within a band context. We distinguish between two basic playing styles: tied, or legato notes and short, accented, or staccato notes. Legato can be characterized as individual notes running into each other. Look for legato playing styles in jazz music and also in rock ballads. Staccato playing emphasises individual notes making them more distinguishable. It is the right choice for funk and heavy rock music, though there are, of course, infinite possibilities between both extremes mentioned.
It is advisable for a beginner not to concentrate on playing particularly fast riffs to start with, but to focus on accuracy. It is always useful to have an underlying rhythm to practice to when not rehearsing with a band.
A metronome or drum machine is definitely advisable. If you're not having lessons, make sure you at least have some good teaching literature to hand in which you can find the fretboard figures as well as note sheets and tablature. The four lines display the bass strings whilst the vertical lines display the bars. The small ciphers on the strings show you which string is hit on which fret; so 0 stands for an open string, 3 stands for 3rd fret, 5 for 5th fret and so on; I = index finger, M = middle finger.