Thanks for the question.
These days, most job hunting is done online using job portals. You can narrow your search done to the positions that suit you as well as your planned destination.
One of the most popular and successful sites is Jobberman, while you can also check out Job List Nigeria, Ngcareers and Hot Nigerian Jobs. I'd also suggest browsing our working in Nigeria page just for a general overiew of the job market.
I also suggest you create a LinkedIn account. It will give you an online presence and portfolio and you may even be contacted for an interview if employers come across your portfolio and like what they see.