The biggest thing I think women do is apologise too much. And frame things as feelings. This is socialised, but very destructive to your professional authority.
Do not be afraid to chip in and don't apologise. "That is very interesting my perspective is/it reminds me of a study on Y" is still perfectly polite, but avoids that half hearted joining in women are particularly prone to.
Also, in a discussion at work, I never 'feel'. I always think, or have a perspective, or a view. This was taught to me by my wonderful first female boss and I think it makes a difference.
Also, don't be afraid to steer conversation away from topics that are male dominated. Natter, natter, natter about golf (assuming you don't play). So you make some comment like "Golf has never appealed to me really, who was it said that it was a good walk spoiled. But I love going running in the early morning and I suppose some of it is the same appeal." and with any luck you are off at a tangent.
Powerful men also often do that thing where they act like they are hosting even though they aren't. As a women you have to careful not to come across as waiting staff, or flirting, but the whole "I think I saw some food over there, shall we go and check it out." can work quite well if you are speaking to someone very informally and want to keep the conversation going a bit.