I practise the piano every day for approx one hour but I'm not sure I'm doing the right thing. I always start off with scales, etc for the grade I'm trying to achieve, but do others do ALL the previous scales as well? And what speed should you aim for. I go slowly to get them accurate as when I go fast I tend to lose them. Then I go through whatever my teacher has set and then play whatever I like. I'm a bit concerned I'm not getting the most out of my practise. Any advice welcome.

I think it is a good idea to do the previous scales as well as your exam scales just so you can keep them ticking over as you will have to know them for the higher grades. However, I wouldn't play all those scales everyday, perhaps you could do one or two of them each day.

Don't try to go too fast on your scales, play them at a speed at which you are comfortable. I think it is better to be able to play the scales accurately and fluently before you attempt to speed them up. Learning scales takes time, the speed will come eventually.

My teacher tells me to do scales when i practise (if I'm doing an exam) but she told me not to do all of them, just about 1/3 of them a day. I think you should start the first ones slightly slower to get your fingers going and then get a bit faster. And I would also start with one of the easier scales.

The ABRMS scale books generally have a suggested metronome marking for each grade - if you don't have one, shout out, I'm sure between us all we can give you the details for any grade!

See my post in your other thread about Chang's book.

I usually do a few Hanon exercises to warm up + develop my technique.

well when i do piano practice, i play the scales 1st just as you do, then i go onto my exam pieces and stuff i like aswell.... i suppose the previous scales would help aswell for you to go over, this is because it will give your fingers more warming up time and if you're ever asked about this certain scale in your theory exam(if you do one) which they prob will as they expect you to know them dont they? as it was part of the previous years coure, then you wouldn't fail at answering q's on it and whatever, also it will stick in your memory better, as my mum ays the better you know your scales and how to play them the easier you will be able to play your pieces, and she's right because all pieces are based on some sort of scale! i hope that helped.

xxxangelxxx

After a warm up, practice the items that give you the most trouble, while your concentration is still fresh. Five minutes of practice with intense concertation is worth hours of mindless repetition. Then move on to the items you need to (eg) speed up in, or develop a better musical expression.
Your warm up should include something you like to play, and the last piece of the session should be something you get satisfaction from playing, to wind you down and relax.

I passed my grade 8 more years ago than I care to remember. I still practise scales regularly. The hands are muscular like any other part of the body. Like an athelete you still need to warm up.
I tend to start with either sight reading or difficult scales, such as octatonic in various keys or indian ragas. These tend to be slow and start your hands warming up. I then move onto velocity scales such as the bog standard ABRSM scales. Then I move onto arpeggios and 7ths. The sevenths I do in the same manner, ex. Cmaj7 followed by, C7, CminMAJ7, Cmin7 and Cdim7, these are continous and non stop.
I then do a short study by Chopin, Czerny or Hanon et al.
The next part of my practise would be new repertoire and to warm down learnt/memorise repertoire.
The amount of time one can practise obviously varies. If I had just 1 hour I do, 10mins scales etc, 10 mins studies, 30 new repertoire, 10 mins playing stuff already memorised.
In my view you dont know a piece until you can play it from memory.

A couple of things I've done in the past (I'm not saintly enough to always apply them)
1) when learning a couple of scarlatti sonatas, I needed to up the speed, so in pencil at the start of each I kept a record of the highest metronome mark I'd acheived. Always practiced with the metronome, and as it got comfy at a given speed I upped it.
2) keeping a log of "troublesome" bars - then these get a few moments attention before anything else
3) practicing a piece backwards - maybe this is more use for big works, but you can often get very good at pages 1 and 2 and it all goes to custard further in. I photocopy the piece, and then just work on individual pages - keeping the original well out of the way so I'm not tempted to stumble through the lot.

generally try and do a few warmup exercises to start.