I really like to take care of my nails, put on some nail polish, and try new methods. Unfortunately, and I don't know if it's the same for you, but even if I like having nice hands, my nails have a hard time growing up, and when they do grow, they broke one by one despite the effort I  make to keep them healthy. For my thumb nail I know I can't do anything, younger, it got caught in between the door, since then when it grows up it breaks, like, every time! For the rest of my nails it may be a deficiency in vitamin.

Also, I am not a nail-art artist, so these tutorials are easy to copy and doesn't required a lot of tools (you may already have them in your house).

Tips:

To avoid split fingernails, file your nails in the same direction.

To keep you nails stronger, and help the nail polish stick easier, apply a Top Coat, it will prevent your nails from getting yellow at the same time.

To apply you nail polish correctly and allow a quicker drying, wipe out the side of the brush to remove the excess of nail polish.

Apply the nail polish in three times:

Finally, for a manicure that seems to have been done at a salon try to not get polish on your cuticles. Apply it a bit upper than your skin and then drag it slowly down.