Does anyone have on how to increase Adwords PPC traffic?

How if we have spent on clicks and tried setting up a couple of extra ad groups using a best performing keywords but can't get enough impressions.

Normally the most specific keywords have highest conversion rates. I´d set up a targeted Cost Per Acquisition (CPA) based on your revenue per action, and go for as many keywords that give you a profitable CPA, as high as you can afford in the paid listings. That´s the only way I see to maximise the traffic, maximising your absolute profit as well.