Tenth, depending on your server and phone, try to set up a system that clearly lets you know or quickly record what or who is calling. If for example, every time you got a call from a prospective client you could flag it somehow and add it to a list so that you can keep track of how many calls you are getting. You could even get a burner phone that has a different phone number so that all of your ad responses come to that phone only. Of course this means that your website and any advertising will have to have that number instead of any other number in order for this to work. Of course I’m talking about cellphones as yours is a mobile business, if you have a shop then you will want another or different number for this purpose.
Eleventh, in the end, you will have to assess for yourself the value of each customer you land. If you are spending say $2.00 per click and you get 100 clicks per month, then you know that you are spending $200 per month for those 100 clicks. Out of those 100 clicks and $200 spent, you get 20 solid clients then you have invested $10 per client gained. Not a bad investment when you look at it like this right? Imagine if you were able to increase your closes? You could actually break even. This takes time and skill but certainly a goal worth working towards.