For software development business LinkedIn ads, content marketing and Google Adwords don't work well. The best and most cost effective method is email outreach.

Try to find the contacts of key decision makers in Bay Area from your target companies. You want to present yourselves as custom mobile and web development specialists and highlight your core competencies to get an initial call to discuss their mobile strategy or software development needs.

Attaching your case studies how you helped other similar businesses and your portfolio can be extremely helpful as well. Try to always focus on the benefits in you pitch that they can get by working with you and point their missed opportunities of not having certain types of software or apps for their business. Clients love that software development companies have not only strong execution but also ideation skills.

Hope this helps. If you have any questions I am also available on call for your convenience.