Physically going to company offices can be a dangerous game. The snootier / larger the company, the more they hate people coming in with CV in hand. Smaller outfits may well be more friendly but, unfortunately, may lack the resources to train you up
Sales and Ops are both good things to do, depending on whether you are of techno-geek / Del Boy mindset, as they will give you a regular income, and keep you in aviation instead of pulling pints or whatever else.
Good luck!