A common trick employed by local SEO agencies is to promise you top rankings in Google and other search engines which they deliver but it does not impact your business.
The reason is that the keywords selected usually are not competitive i.e. they are not searched a lot in search engines and as a result do not deliver good quality traffic to your site.
Ideally the selected keyword list should contain a mix of 20% highly competitive keywords, 60% average competitive keywords and the rest 20% easy and long tail keywords. This ensures that your SEO initiative does not get bogged down due to highly competitive keywords or succeed too easily without delivering results.
When your SEO agency submits their list of keywords ensure that none of the keywords are already ranking well. This is another trick unscrupulous SEO agencies use to show unearned results. Selecting already well ranking keywords let the SEO agency claim credit for something already existing and does not add any value to the SEO effort. Also it is mostly likely that these keywords are providing the bulk of the existing traffic and continuing to promote them will not increase your traffic.
Many times an SEO agency will point to good rankings in the search engines and also an increase in the site traffic but there will be no significant improvement in sales or enquiries. Do not let the SEO agency of the hook. Ultimately SEO is not about traffic or rankings but about improvement in the bottom line. The agency must revisit its selected list of keywords and make sure the results are delivered.
If the correct keyword mix is selected and promoted you will get a good and healthy increase in all three factors i.e. rankings, traffic and conversions. Mind you such results will not come overnight and any good worth the money SEO effort is always a time consuming upwards process. After all you are trying to break into a new market or increase your share of the sales pie and that is never easy, online or offline.