Keep your statements clear, short and factual. After you've spoken, the Councillors will debate the issues among themselves. Although they will often mangle your points beyond recognition, you won't be allowed to speak again. This is why it can be good to send advance information kits to Councillors that you will be deputing to, so they have some idea of what you mean. When you speak, you can address their concerns directly.
Some committees have more influence than others, usually the budget committee has a strong impact.
Different committees may recommend different things to the Council, for example, the TTC Committee may vote against a fare hike, but City Council will approve one for budget reasons. You may also need to persuade several committees before your proposal is ensured of being passed. If it has financial implications, it must be approved by a budget committee. Think of a strategy Find out about the people on the sub-committee you will be addressing. Some Councillors have more influence and power than others.