If you have a garden, it is a good place to start. Set up a feeder or two and practice getting good shots.
Both in the garden and elsewhere it is useful to know the habits of birds and what they are likely to do.
For example, the finches tend to sit and stay so when they are on a feeder they are likely to stay for a while.
The tit family rarely stay still for long and grab food and fly off, and the smaller members of the family, such as coal tits, move very quickly.
Some birds are much more tolerant of the proximity of humans than other. In the garden, getting close to a robin is easy and I have also found coal tits to be be fairly tolerant. Jays, woodpeckers, magpies are, in my experience, very wary and tend to fly off very quickly.
Dave