I've made a conscious effort to appear intelligent in several periods of my life.
The first was during high-school. Now I didn't use any of the tricks mentioned in the OP, but there's the cultural gap there: I always had an excellent eyesight, so no reason to wear glasses, I'd never heard in my life about Shakespeare or classical music, or liberal politics, and actually hadn't read a non-school book before going to college. Still, I was studying hard and developed by that time a dismissive attitude that later in life I found very hard to give up. I weren't too willing to answer teachers' questions either, but I made a point of leaving as clear as possible to classmates and teachers that I did know the answer. The point of all these was to have the teachers talking to my parents into letting me go to the university.
Then at the uni I needed also gain good impressions so to have good references in the case I needed those later. I had to somehow balance the first impression I gave when I showed up to the uni, of the shy, introverted child from a village, clueless to most social situations and without any "intellectual" background, so I used a couple of similar tricks: studying very hard, being sure I totally understood the processes before doing anything and only talking about stuff I was 100% sure about. By that time, I also had discovered books and started to slowly became an obsessive reader, which would add to the "intelligent" look I tried to have.
Finally, when I moved in the country I'm currently residing, I fell immediately in the defence, since I had to deal with very competitive people. So, especially the first months, I was deliberately trying to look smart and intelligent and also I started looking very serious, another attitude that I got so used to it that I cannot give up by now.
Never used the poetic stuff, however, it would be too much off-character.