1. Get into all the directories sooner. In the bad old days there was really only two or three directories on the net. At the time I didn't feel it was worth my time to bother as I was getting major publicity from my network show anyhow. Now that I'm independant, though, it would have been nice to have an established account on some of the more established direcories to flip into my new show.
2. Have professional bumpers and intro/outros made. Somewhere around who #10 of the old GNU/Linux User Show I had professional intros made. I never did bother to get pro bumpers (the sound bytes that separate segments of the show) made. Our current JaK Attack! podcas has professional bumpers and intro/outros and it really makes the show sound much more professional. If you swing by Radio Daddy, you can likely find someone to make them for you for about $10-$15 a pop.
3. Do less interviews. Yes, I said less. I'm a huge advocate of having someone, anyone, other than just the podcaster on the show. Interviews are good; co-hosts are better. There was a time when I would do interviews for three or four shows in a row. The problem with that is both my listeners and I came to expect them. I started to feel bad when I didn't have an interview on the show and that's not good. Interviews are good, for sure, but whatever you do on your show ensure that it's either sustainable or you don't fall in love with it.