We have similar issues with handwriting - formation of letters, spacing, stamina is low and he complains its painful and is reluctant writer who finds it hard to organise thoughts. He is 10. Our son has dyspraxia and dyslexia and ADD so these all interact. It is possible to have dysgraphia as a stand alone but would be aware of co-occuring things just in case.
Things we and school do - Gross and Fine motor movements (writing involves things like shoulder and pelvis stability to fix points to work from a stable base). Wrists and elbows also come into play along with, finally the fingers and how the hand grips the pen - can be too tight (sometimes if they are a little hypermobile in finger joints this hurts them when writing) or grip too close to nib of pen/pencil.
Things to try - warm up hands with play dough or other finger exercises- rip paper, paper hole punch, etc before writing. How are scissor skills?
Movement breaks in between writing to flex hands and then go back to it.
Handwriting programmes like start write stay right are often used by schools. Or you can buy online. We offer incentives such as lego comic for x pages done. Little and often is key.
National Handwriting Association, pintrest and OT assessment of handwriting and drawing shapes useful. You can get an assessment privately if long wait via school/NHS. You can also get handwriting tutor for home if you have the means. I have seen good progress for kids with poor handwriting via this route - before and after pics on FB for dyspraxia groups.
We made a small spaceman for gaps between words and use magic lines to help tall/small letters make sense.
How old is your DC?
Interventions best started young alongside use of tech as poster mentioned above - lap tops with word banks, speech to txt software and so on.
Its harder as they get older and they feel they have repeatedly failed to master writing and then it becomes a hangup where they feel unmotivated to persevere. It can really get better with the right kind of interventions - DS does touch type with TA and handwriting x 2 week for 15 mins. Over a year or two his writing has improved a lot. Still like a drunken spider has been at the ink but is sobering up nicely!
PM me if you want any more specifics. I would also echo other poster who said print is fine, if it increases legibility and he/she finds it easier - well lets not make life hard with a million cursive wiggles eh?
Multi sensory can help too - 'write' in the air (big moves), on each others backs/hands, on velvet, carpet etc then in flour, paint, glitter etc Advantage of invisable writing is that they are not confronted with lines that are 'wrong' iyswim.
Write Dance good for this in kids up to 8 or 9. Its a Dutch Book in English - methods used internationally. Pre Writing patterns essential to practice if the child has difficulty with shapes in letters - W O diagonal strokes as in K - if you google pre writing patterns you will see what I mean.
Hope all that helps. Make it low stress and as fun as poss.
Start with couple of mins and work up as they get more confident.