It is difficult to give a definite time frame for SEO efforts to show results, as they depend on a number of factors. These factors include the choice of keywords, the competition in your industry, rate of back linking to your site and a few others. Depending on these factors, the results of your SEO efforts may take a short or a long time to show.
If you are using purely organic SEO for your site’s promotion, you may have a wait of up to 3-6 months to see results of your efforts (of course, this is assuming that you have chosen moderately competitive, significant traffic keywords). Organic SEO although an effective long-term solution, takes longer to show results on its own. The good thing about organic SEO is that once you finish the groundwork, it gets easier from then on. You just need to keep making small changes as required in keywords, content or link building strategy. Unless you want to redesign the whole site, you don’t need to put in too much work.
If you need quick results, combining a PPC campaign with your SEO efforts can be a good strategy for lead generation. Slowly, as more and more relevant sites have links coming back to your site, it will decrease the need of running expensive PPC campaigns to generate leads.
Every SEO company will advise you of the need be patient with SEO efforts, as it can take a while before the results are realized. You also need to remember that good quality content, navigation and accurate keywords are a must for the success of your search engine optimization efforts.