There are a lot of scales, but the three basic are major, minor and melodic. There are also the arpeggios, broken chords that can be major, minor, etc. like the relative scales. We can talk about scales for years, they're a lot! So, let's move directly to the advices that can help you to enjoy your scales and gain the maximum benefit from time spent learning sclaes!
Use scales as a warm up. Playing sclaes must be the first thing you do after assembling your instrument. This serves to prepare the instrument and make it to do the best and help you to improve your technique and your sound. Pick some easy scales to begin with, like F major or E minor. Start with a slow metronome speed and increase the speed gradually, for example you can start with 60bpms and increase a bit the speed every day, so, at the end of the week, you can play the scales at the speed of 75bpms!
When practising a scale, make it sound musical. In this way the scales won't be boring. You can change the rhythm, the expression of the sound or the dynamics. You can play them swing or in triplets with various articulations like slurred or tounged. It's fun! Try it, also with a backing track. You won't be bored anymore!
Always play the scales at a speed you can manage accurately. If you are repeatedly making mistakes, you are playing them too fast. Slow down. Playing them fast and wrong means that you are actually learning them wrong!
Memorize them as soon as possible. This can help you, for example, to improvise. If you know the scales, it become easier for you to understand quickly what you can play on this or that chord and your solos become more beautiful! You can follow the chords and play the best phrases on them and not after they've passed.
Learn one scale at a time. This is very important. Set yourself a “scale of the week”. Most people, average around a week to consolidate a scale if they practise it daily. Even if you are a quick learner, avoid the temptation to learn too many at once. It’s confusing and you mightn't learn well the scales. In this case, you'll have to do it all over again!
Learn and practise the related arpeggios. Arpeggios are broken chords and should be learned along with the scale. Thet're formed by the first, the third and the fifth note of the scale.
Play your scales regularly. If you learned them properly, you won't ever completely forget the scales. But, if you don't play them often, they can become very rusty. So, play them regularly as part of your practice routine. Start with those that you know better and finish with the one that you are currently learning.
Enjoy playing your scales. Scales need not be boring. The more you play them the easier they become and the easier they become the more you will enjoy playing them. Once a scale is learned in strict time try varying the rhythmic structure. You could apply Latin or funk rhythms, for example.
Create an imaginary audience. Perform your scale. Enjoy playing the scale. Play it expressively, and all the while concentrate on the three T’s: Tone, Tuning, and Timing.
Recognise the benefits. As you learn more scales you are gradually laying the foundation of a secure technique. Not only are you consolidating finger patterns for all the different keys, you are simultaneously improving your breathing, tone, timing, intonation, articulation and aural skills.