I like asking bartenders about new beers. I enjoy trying their recommendations and determining whether I agree with their assessments but more importantly than that: I'm allergic to hops. As someone who enjoys beer this is a pretty lousy allergy and I need to be selective about what I drink or else I'll suffer. When I ask for a suggestion I tell the bartender about my allergy. Without that piece of information that wouldn't be able to offer an effective recommendation. They need to know the criteria if I expect them to do their job effectively.
If I don’t agree with them I don’t get mad. I get a different drink next time, a little better informed. I won’t waste time being miserable about a bad beer. It’s not worth it.
You have expertise. Share it. If you’re not offering the whole of your skill and experience please ask yourself, “Why not?” Are you not being paid enough? Is it a fear that you’ll be judged? Do you not care about the project? You get what you give. If you’re holding back it’s likely the people around you are following your lead. And if you don't have enough information to offer a recommendation, ask questions. Learn the needs and values of the people around you (clients, friends, family, etc).
Do you want to be valued as a creative person or a tool to execute some else’s ideas? Not all of your suggestions will be followed but the more you offer the more you influence.
One last thing: don't get bent out of shape if not all your suggestions are followed. Ideas are cheap and plentiful, people who remain positive, supportive and invested in success are worth their weight in gold. You are more than your ideas. You're friends and clients will appreciate your willingness to move forward regardless of whose idea has been selected.