SEO is search engine optimization. Making your website structure and content great for the search engines and website visitors.
SEM is search engine marketing. This is geared more toward converting website visitors into customers using A/B testing, analyzing results, etc.
SMM is social media marketing. Social Media is off-site marketing for your website but also includes adding ‘like’ and ‘share’ links to your website.
The first would be Keyword Research. You can follow the link to read an in-depth tutorial on this. With the keyword research, you can determine what direction to go by finding out what people are asking online, what they are looking for, what phrases are searched for the most, and how hard it is to rank for each phrase.
Second would be content creation from the results of the keyword research. You can answer the questions you find from the keyword research on your website. You can write about topics that seem to interest the general public the most that you find from your keyword research as well.
Third would be on-page optimization where you would tweak the content, meta title tag, meta description tag, provide online tools, content, etc that will help you rank for keyword phrases that are searched for a lot that has low competition. This info you get from your keyword research as well.
Competition Analysis can be done to find out how your competition ranks for the keyword phrases that you want to rank for. Some of the things you come up with are how many people link to your competitor, which of those links are effective for them, what type of links are they (like a forum, directory, links to page content, etc.). Then you can apply the principles that work for them for your own website.
Social media marketing works well for people who are ‘people persons’. By offering advice, answering questions, and letting people on social media know about your services and sales is a great way to get the word out. Claim your Facebook page and merge any duplicate Facebook pages out there. Claim your Google My Business page as well.
Word of Mouth. Oops, this should have been #1. Word of mouth has been and will always be the main source for customers. Display testimonials on your website, have a form where people can leave testimonials, create a Google alert for your business name so you can get notified whenever someone talks about your business, etc.
Pay Per Click campaigns can be used for quicker ranks but people are more likely to click on an organic result than a pay-per-click result.
For localized rankings utilize a service like Moz Local to get your foot in the door and help you rank locally.