That’s quite important, it isn’t only the work you do, but how you explain it the design and the process to others. Back your design intentions with logic, explanations and facts; give them a reason to be that way, how did you find out that was the best solution. You could practice with some friends, we used to do that at uni, I don’t see why you couldn’t do the same now.
I’d also recommend you to ask friends from uni or previous jobs whether their company is looking for someone, that’s how I got my current position. Having a good network is quite important as well.
I would like to give you some feedback on the portfolio, but internet is quite slow at the moment here. I’ll if I can take a look during the weekend.
Cheers and good luck!
Ale