I’m going to work backwards through the methods listed above. Search engines, while the most common way for “good” traffic to come to your site, are one of the most difficult methods to do well. So, it’s going to get left until the end.
If you watch your web server statistics you will notice that direct access is not a common method for people to come to your site. But the traffic that comes from direct access will often be very good, that is very likely to be looking for your services. Often they saw your web address somewhere and are typing it in.