When you know alcohol will be served, it's important to have some resistance strategies lined up in advance. If you expect to be offered a drink, you'll need to be ready to deliver a convincing "no thanks." Your goal is to be clear and firm, yet friendly and respectful. Avoid long explanations and vague excuses, as they tend to prolong the discussion and provide more of an opportunity to give in. Here are some other points to keep in mind:
Don't hesitate, as that will give you the chance to think of reasons to go along
Look directly at the person and make eye contact
Keep your response short, clear, and simple
The person offering you a drink may not know you are trying to cut down or stop, and his or her level of insistence may vary. It's a good idea to plan a series of responses in case the person persists, from a simple refusal to a more assertive reply. Consider a sequence like this:
No, thank you.
No, thanks, I don't want to.
You know, I'm (cutting back/not drinking) now (to get healthier/to take care of myself/because my doctor said to). I'd really appreciate it if you'd help me out.