Analyze where money goes

• Set dynamic conversion tracking

Ads optimization

• do ROI based optimization
• optimize your ads based on their ROI metrics
• make separate campaigns for high ROI ad groups
• make separate campaigns for different languages, geographic targeting
• create negative keywords in a shared folder, and add it to relevant campaigns 
• extend your negative keyword lists at least once a week
• use flexible bidding for devices, days/hours, geographic regions, demographic target etc.
• set automatic budget increase for the best days of the week with higher search volume, and budget decrease for the worst days

Reference
[1] https://www.quora.com/What-are-some-Google-AdWords-best-practices