Simplify your account structure. Granular campaign structures aren’t necessary as automated bidding will work across all account structures.

• Base your campaigns on objectives - Automated bidding is objective-based bidding, which means a single campaign should generally have the same type of objective. For example: if you are optimizing for clicks on certain keywords but for conversions on other keywords, they should get their own campaigns.
• Avoid campaigns that are limited by budget - Campaigns that consistently hit their daily budget have an artificial limitation on performance. Ideally, you’ll want your daily budget at least 20-30% higher than your campaign daily spend. This allows for quicker learnings when using Target CPA or Target ROAS and more volume at a similar efficiency. Use Maximize Conversions strategy if your campaign consistently hits its daily budget. 
• Don’t worry about maxing out Impression Share (unless your objective is visibility) - An impression share lower than 80% is expected for any campaign on Smart Bidding. This allows for growth opportunity. If Impression Share is higher than 80%, it may be time to expand your reach.
• Make ad groups (or campaigns) coherent and high volume - Relevance within ad groups is still important. Relevant ads are more useful for users, and click-through rates and conversion rates are often better with high relevance from search term to ad to landing page. With Smart Bidding, volume is also important. The more volume associated with your objective, the quicker Smart Bidding can learn and improve.
• Use broad match keywords to scale performance - Smart Bidding works with the text of the query, not just the keyword. Using broad match keywords allows the machine to find additional queries that help you reach your objectives.
• Add audience lists to increase Smart Bidding efficiency - Smart Bidding accounts for audience list performance. Adding lists to a campaign or ad group on Smart Bidding gives the automation more information and can improve efficiency.

* Nguồn: Google