The effort was twofold. The first and most important step was to ensure relevance between our ad copies, keywords, and LPs. We tested using the keyword in headlines and display URLs, and tailored landing pages to include the keywords.
The second step was to ensure that we were giving the keywords a chance to see a good CTR through a better average position. This was done by increasing bids for a few days.
Not hard, but not guaranteed. CT for examples.