If I had to pick only one scale to play for the rest of my life it would be the major pentatonic scale. Okay, that's cheating a bit as, by learning that scale, I also get to play the minor pentatonic scale (which is related). SO much music is made from the five notes that make up a pentatonic scale. You could write hours and hours of bass lines with it and not get bored.
This video goes in detail into how you can create great lines, solos, and fills with this wonderful scale.
Make sure you check out the lesson on the minor pentatonic too.
Major Pentatonic Shapes For Bass
Learn these shapes across the neck for C Major Pentatonic.

Look at how A Minor Pentatonic is exactly the same shape:

This is why C Major and A Minor are 'related' - they contain the same notes. So learning a major pentatonic scale is two-for-the-price-of-one, making your life easier!
Download the two shapes below.
Here's the backing track used in the video and chord progression below it.
Chord Progression
The backing track uses these chords:

Go through the video and use the backing track with the new shapes you've learnt to make up some lines, fills, and solos. Have fun and revel in the magical power of this cool scale!
great content. Question so if I have a song that has the chords A. D7. A. E7. A. Do I play an A Major pentatonic scale? or what? How do I know based on the chords in the song do I play a major or minor scale and which one?
Thanks
Dean-O
Thanks, Dean-O. That’s like a major 12 Bar Blues. So, A Major Pentatonic would work, overall. It’ll be great for fills and solos. You can also play a major pentatonic over each chord (based on the root of that chord). It’s really all about learning harmony and how chords function within a key. It’s called diatonic harmony. That’s a great start anyway. There’s a lot more you can do including breaking the ‘rules’!
How does one tell major or minor pentatonic scale?
Major Pentatonic comes from the Major Scale and has this formula: R M2nd M3rd 5th M6th
Minor Pentatonic comes from the Minor Scale and has this formula: R b3 4th 5th b7
They have different intervals and different formulas. If you don’t know about intervals and scale formulas, use the search button on the site. Thanks! Dan