I have been teaching students on scales.
What is the right way to practise scales (legato)?
I'd recommended slow practise, striking each finger on every key, and getting the thumb right below and ready on the next note and minimise all unecessary movements of elbow.
Any other opinions?

Thanks

Don't forget to ask them to listen to themselves, thinking about playing legato can acheive wonderful things without using up all the brain space with what their fingers, elbows and wrist should be doing.

Are you talking about beginning to teach scales? I like to do this well before we think about exams for various reasons. It helps with learning to get the thumb under without jerking the elbow - helping also to eradicate flat hands. And it also helps with an understanding of pitch. Take the following group of scales:

C Major
G Major
D Major

and there are others, but these are the easiest.

The fingering is the same for all. Therefore, if you teach them doh, ray, me, they can learn that 4 in the RH is always on tee, and 4 in the LH is always on ray. remembering where 4 comes is often a bit of a problem with youngsters in two-octave scales. I find that this method helps them to see the patterns in scales, rather than simply learning by rote. Get them to say/sing doh, ray, me, etc, as they go along.

A slight "problem" with this is that in the AB syllabus, F Major is included in the Grade 1 scales, which requires 4 on RH Bb - so they need to look at this one a little differently - just to be awkward! (Another thing I liked about Guilhhall!)