Do you routinely defer the floor to others before you are finished? Giggle when nervous or, worse yet, laugh uncontrollably? End your statements with a lingering request for support? Do you work to be seen as the always-agreeable-can-get-along-with-anyone person on the team? Start your recommendations with qualifiers such as, "I am not sure you are going to like this idea, but." Not ask all of your questions because you feel you may have taken up too much meeting time already? Do you do any variations of the above on a regular basis?
Yes? Well, stop that right now.
When communicating, be prepared and be professional. Articulate your position and state the reasons why. Don't soften a message that needs to be heard and don't think for a minute that you deserve any less respect than the person sitting next to you.
Quit standing beside your power and step into it. Now.