Without knowing specifically what you mean by "on page" and "off page" work, it's difficult to make meaningful suggestions. I don't think anyone here is prepared to put together a complete optimization plan for free, so perhaps it would be good to start by identifying specific areas where you feel you need further advice.
There's been a lot of material posted here already with SEO advice. Have you read those threads? If not, I suggest that as a starting place. If you have read them, are there any specific areas about which you have questions? That might help us begin to narrow down what sorts of suggestions would be helpful.
SEO is not an overnight solution. Depending on the market the site is targeting, the level of competition and how realistic the expectations of the site owner, getting traffic via SEO may take months. Depending on how long the site has been in existence and how long you've been working on optimizing it, you may simply need to give it more time.
Beyond that, what else (beyond SEO) is the site doing to bring in more traffic? Organic search should always be the "icing on the cake," not the core of the traffic strategy for any site. In high competition markets, SEO alone may never
be enough to bring in sufficient traffic -- and even when it does generate a lot of targeted traffic, that traffic can go away overnight if Google decides to change something. That's a precarious position for a business to be in. For the long-term survival of the business, there must be some sort of backup process for generating traffic in the absence of search traffic.