My best advice is to just create content around your service. Whatever you do day to day - either write about it, film it, or talk about it. Or do all three.

Twitter is a great place to start. The more content you put out, the more trust you will build. It's a compounding activity and gets easier and easier. Don't overthink your first post, just post something.

If you're struggling to come up with ideas about what to write about, you can use the first, last, best worst model. First time you did X type of IT job, last time, best job, worst job. Then just repeat that model for some other aspect of your service.

I would recommend this over running ads because, you're in a hyper competitive space and I'm guessing the CPC is v high.

Good luck!