I would second a glass or crystal nail file, I've had a few the best is the small OPI, it will last forever if you do not drop it or sit on it. The reason I like it is that it is then and for short nails and corners it is still nice and easy to use. I believe that the glass files, seal the free edge of the nails preventing water from getting in and the splitting.
Have tubes of cream in every handbag and apply to hands and nails whenever you think of it.
When drying your hands dry well around the nailbed and you will keep cuticles at bay.
Go easy on buffing, if you make the surface of your nail too shiny then polish will not adhere well.
Take a prenatal vitamin, or supplement with biotin.
Use a hardner, nail envy does work but it will make your nails go yellow if you use it all the time.
Keep your nails polished, use a base coat and top coat.
Best top coat in the world is in my mind nails inc 45 second caviar one. Seche vite is also OK but goes thick before I finish it. I'm currently using the crystal glaze one because its cheaper than the nails inc and Seche Vite has a chemical in I don't like to use when pregnant.
If you buy from Sally's (need a friend with a trade card) then Seche Vite is only about £4.59 plus VAT, although vat free day once a month on a Thurs. I always get a bit more wear from OPI and you may find if you combine the same brand base and top coat that the wear is better. I find this for nails inc for definate. Hope this helps... I'm a bit obsessed with nails and professionally trained although have yawn job in IT.