When working with a newbie you need a lot of patience. It helps if you have experiences of your own from when you were a newbie in the industry. You can't expect too much from them and you can expect a lot of mistakes.
They key to turning them into an experienced developer is spending the time to mentor them. Ultimately every developer will be mentored by someone...sometimes even by the very code-base they are modifying (ie they'll copy what they see others doing). If you leave the mentoring up to chance, it is highly likely that they can pick up poor habits that may follow them for years into their professional life.
It does take time to mentor people and it will often seem like time you can't afford to spend because of your own tasks...but I believe it is time that you can't afford not to spend.
Mentoring a newbie need not take up 100% of your time. There is a lot to be said for developing a friendship with the developer in question...thereby making them more open for feedback and more likely to come to you for advice....and making the task seem less like a chore.
There are heaps of good books on the subject so you should probably look into purchasing a couple of them...just note that often these books won't be specifically about IT but more about people development.
The initial steps I would take are:
- Make them your friend
- Spend time with them
- Mentor them whenever you can...in person, by email, by example
- Be patient with them as they make mistakes...cause they will!
- Read books on how to become an effective mentor