Waiting lists for daycares can be rather long, and even if you do put yourself on the list when you are still pregnant, there is no guarantee that your child will be able to attend the daycare facility of your choice. It certainly helps your chances, though, so it is worth a try!
The earlier you register for the waiting list, the larger the chance that you will get your child the spot you are hoping for. The second and third trimesters of pregnancy are probably the best time to start looking. Looking into different types of day care facility also takes some time. All daycare centers are definitely not created equal. There is a lot of difference between daycares when it comes to what activities they do with the kids they are caring for, specific educational philosophies (such as Montessori or Waldorf), and the daycare worker/child ratio.
The distance of your chosen daycare to your home is also an important factor to consider, along with the working hours. It is not necessary to sign your baby up for daycare to get them in or at least not in all cases but it will definitely help you have more options. Looking for child care with a short notice will limit you a lot, and starting early will ensure that you will have the care you feel most comfortable with for your child.