Agree with Dan.
The key questions are:
# how much do you want to invest (do you have enough to invest in ~20 companies)
# can you afford to lose it
# what is your current basis of knowledge.
# how much time do you have to learn

If you have time and money, go EIR for a vc/angel for free (have a friend who did this) and learn for a year.

If you only have $10k, don't bother.