Of course, all the good ideas in the world will mean nothing if you don't know how to present them. There are many ways to do this appropriately. First of all, there are ways to present ideas to a client. Second, there are ways to present ideas in a portfolio. Third, how to present ideas to coworkers
There are several things to keep in mind when presenting to a client.
It is pretty standard to have boards of some kind with your project on it and perhaps a little bit of text. However, mockups and miniatures can be a really substantial part of a presentation as well. In many cases a mockup would be far more effective than boards. The visual example below shows a project board that was used in a presentation. The pieces on the board were also included in the presentation, as mock-up material. Personal appearance is pretty important as well. Sloppy dress distracts from a presentation as well as extremely excentric dress. The best advise to dress well, but be careful not to be distracting. In many cases a presentation will include several ideas or variations leaving the client to pick their favorite. Therefore a good presentation should gently lead the client to pick the "right" choice.
There are several really good things to do in a portfolio to make your projects pop. First have a theme. Your portfolio is every bit as much a design project as the items in your portfolio. It is also important to have multiple versions of your portfolio on hand, one in print, one electronic, and one on the web. That way, if you end up with an interveiw, you have something organized, tangible, and finished to take with you, but you also have something on hand in case a face to face interveiw is just not possible. Good examples of portfolios can be found on the research page of this website.
What I have noticed most about presenting to coworkers is that this always goes best when I don't have an expectations. If I go into it thinking, "they are going to LOVE this project" or "this version is way betterthan that one so I will spend more time on it" then I usually end up backtracking and can't get straight to the point. I have also noticed that the visuals I have don't really count for as much as the verbal explination of my visuals. If I can't communicate my idea the presentation will not go well. My usual battle plan in this situation is to explain to myself each peice I want to present and then work hard to be open to all suggestions.