Looking for answers, looking for answers... I read tips like "Keep ad groups to 1-2 keywords" and "Only use exact match" and "Use phrase match to find new exact matches" How do these tips add up? If you get more exact matches you are easily going to exceed your 1-2 keyword rule, right?
The new keywords can be added in a separate ad group. Anyway, 1-2 keywords-per-ad-group is acceptable only for keywords with significant amount of traffic, say, at least 0.1% of the campaign's cost. Having 2 keywords per ad group isn't a goal, only a mean. It'll improve the campaign only if the users who triggered those 2 keywords engage better with a separate ad/ads (i.e. higher CTR). This compared to the original ad/ads in the original ad group. Another possible motivation for using small ad groups comes up when the campaign is set to ad-group-level-bids, i.e. when the Conversion Optimizer is enabled. As for "Only use exact match": If you can afford it - the combination of Modified Broad match with many negative keywords is also recommended. This might create a "Broad match trap"/"overlapping search terms". Nevertheless it can be overcome by the campaign structure called "Match Type Silos".