It depends where you want to work. You need to go where the companies you'd like to work for look for staff. If you're looking for a role somewhere big and well known then Google, Indeed, etc are a good bet. If you want something more start-up oriented then sites like workatastartup are good. If you want something a bit more niche and unusual then using your LinkedIn network works well.

The last few times I've looked for a role I've just googled for companies I'd like to work at and browsed their careers pages. If you have specific things you're looking for (eg more "I want to work for one of these companies" rather than "I want to join any company within these criteria") then going direct can work very well. Companies seem to like candidates who approach them too because it saves them a fortune in recruiter fees...