The nomination form usually contains a section to list which wards you are interested in - think carefully about this in advance. Putting down all wards is one way of getting your information spread widely, but a more targeted approach may get you more noticed and help you argue that you are really interested in representing just a few wards - perhaps those closest to where you live.
You are entitled to a ward membership list - ask to see it and see if you know anyone who would be prepared to nominate you and support you
If not, ring the ward secretary or chair and ask what the important issues are for them and what they are looking for in a candidate - most candidates simply tell wards what the candidate is interested in, asking for members' views will get you remembered.
If the ward already contains sitting councillors it will be harder to be in with a real chance of getting selected - find out where the vacancies are, where people are stepping down or Labour does not currently hold all the seats, and target those.