Who is your target audience? Age, gender, interests, profession. Research and find out what social media networks they prefer.
Don't overwhelm yourself by signing up for too many social media sites at once. It's better to focus on one or two platforms first. Once you feel comfortable you can add more.
Consider you website your homebase. You ultimately want to use other social media sites to push users to your homebase, especially if you're selling things off your website. Your blog will help establish your brands voice. Display other social media icons on your blog so potential customers can connect with you. Also, incorporate share buttons on your blog so when a reader sees valuable information they can share it with their online networks.
Social listening means monitoring your social media sites and responding to comments, mentions and feedback even if it's negative.
Create a daily schedule and a monthly editorial calendar. Set goals for yourself. For example, you can set a goal of one blog post a week, and one social media update a day. That takes care of content creation. Next, set a goal to respond to at least two mentions a day.