I decided to trim my own hair tonight & up to now it looks pretty good although I don't want to scrunch it out till morning (it's still airdrying).
What I did was section my hair with duck bill clips so the top layers were out of the way & then started on the bottom layer, I then parted hair in small vertical sections & pulled them at a horizontal angle, lining them up with each other as I went along, I trimmed about an inch all over. Basically how most hairdressers cut it, although I can't say my effort will be quite as even.
I then trimmed around the front by pulling it forwards as I am trying to line up my grown out fringe (just below chin) with the rest of my hair.
The shape definitely looks better already & my curls seem to have bounced back a bit too, they had been getting rather droopy of late.
I will judge the success of this trim better tomorrow or at the weekend when I diffuse.
U.K curly

3A Curly Twirly.
Golden brown (coloured to cover grey).
Low poo: Dr Organic, L'Oreal Everpure.
Conditioner: Dr Organic Argan Oil.
Leave In: Aussie, Curl Harmony.
Gel: Curl Keeper Original, Umberto Gianni.