There are few main variables that can impact application performance which you can help control and manage:
Getting cluster sizing correct for your application load,
Structuring documents for efficient reads/writes,
Using SDK methods which are more efficient for the operation you want to perform.
Optimize your use of Couchbase client connections.
Correctly sizing your cluster is one of the most important tasks you need to complete in order to provide good performance. Couchbase Server performs best when you have smaller documents in your data set, and when a large majority of this data set is in RAM. This means you need to take into consideration the size of your application data set and how much of this data set will be in active, constant use. This set of actively used data is also called your 'working set.' In general, 99% of your working set should be in RAM. This means you need to plan your cluster and size your RAM data buckets to handle your working set.