Search Engine Optimization is an ongoing program and results vary from project to project. Within competitive industries, it can be even more difficult to move the needle, however, on average, this diagram will give you an idea of how long it typically takes to get improved results (note, if we’re engaging in Adwords / PPC advertising in conjunction with an ongoing SEO programs, results may be noticed much sooner, typically within 90 days).
Outlined in your proposal will be various milestones, goals and metrics that are within our control that we hope to improve upon such as conversion rates, organic traffic increases as well as a marked increase in lead generation.
The following gives a nice visual representation of an averages companies success with an SEO campaign:

To learn more about SEO timelines and how things are priced, you can visit our blog.