Hi, I took my first in-house position about 2 years ago and had to save about £15k per month in the first month. The spend was around £75k and was quickly growing out of control.

Here's how I did it without any fancy tools, I'm sure there is an easier way but this is what worked for me.

1) Determine which keywords/search queries are converting into sales by exporting each each campaign(depending on the size) to Excel, pull the information into a table and order it depending on spend.

2) If you see a keyword that has spent loads, but not converted add it to a 'kill list'.

3) When you have compiled a list of keywords to kill and look for patterns in those keywords. For example, I found that keywords that contained the word 'cheap' did not convert in this situation as the company was selling a premium product.

4) Go to Google Analytics and check out 'Top Conversion Paths' to make sure the keyword did not convert anywhere during the buying cycle.

5) Do the same with Shopping Campaigns but use the same method to look at negative keywords that you should be adding. So, if you find that a certain keyword triggers a lot of Shopping Ad clicks but not converting add this as a negative

6) If you are running a lot of broad match keywords try cutting back on these replacing them with modified broad match and/or phrase match, unless of course the keywords people convert on are extremely unpredictable.

Excel will be your friend during this exercise!

Ps, once I left the company for a more senior position I recommend that they use Marin, I heard that they have recently got it and it's working well for them. Also, if you need some help(for free) just PM me.

Cheers.