The final step of your SEM optimization is to measure and improve your results. You should track and analyze key performance indicators (KPIs) such as impressions, clicks, conversions, revenue, ROI, CPC, and CPA. Additionally, you should set up goals and benchmarks to evaluate your progress and identify areas of improvement. Google Ads' tools and features, such as conversion tracking, campaign performance reports, optimization score, and recommendations can be useful for this. Similarly, Google Analytics' tools and features such as goals, attribution models, segments, and custom reports can help you measure your SEM results. Other tools like SEMrush, Moz, or Ahrefs can be used to conduct keyword research, competitor analysis, and SEO audit. Finally, you should test and experiment with different variations of your ads, landing pages, keywords, bids, and targeting options to apply learnings from your tests to optimize campaigns and strategies.