1- Start by creating a web presence for yourself, a simple bio website that explains who you are and what you do a long with links to some of your work.
2- Create a GitHub (or Codepen) account and open source any reusable code, plugin, etc. Just make sure you actually own the work and are allowed to do this.
3- Create a profile on UpWork and find freelance work there.
4- Pick a side and a language and start specializing a bit. It's great to be well rounded and have lots of skills but it is a much easier sell to say I am a front end engineer and love building UIs, I am experienced in CSS, JS, Angular, etc. versus I do C, C++, front-end stuff etc. You can mention that you are comfortable on any side (front or back) but it is better to say which is your stronger skill.
Good luck!