The best way to file nails is in long strokes in one direction – this prevents flaking and keeps them strong
I really believe that good nails, like hair, start from within. Check your diet; are you getting enough iron and keratin rich foods?
Gently buff any peeling bits off then rub Vaseline onto your nail bed to seal your nails. Vaseline is good for everything!
Regular manicures are the only thing to sort your cuticles. You can buff them off slightly but it’s tough to cut them yourself
For nails that curl at the top, I would try and keep them short or perhaps try an acrylic overlay which will work as a brace to keep your nails straight
If your nails are discoloured from nail varnish then you must use basecoat. I’d recommend lemon juice on cotton wool to get rid of the discolouration and then sweep over again with acetone
On when to give your nails a break from polish: It just depends - you know your own body, you know your own nails. If they’re weak and peeling then yes, give them a breather. But if they’re strong and tough then they can handle the polish
On nail art: Practise, practise practise is all I can say. The more you do nail art, the better you get.

The future of nail art: It’s now possible to digitally create your own designs