In June 2020, I passed the AWS Certified Solution Architect Exam after almost preparing for 5 months ( an hour or so everyday) and I was so pumped that I decided to take another AWS exam. I started preparing for the Developer Associate exam at the end of June and cleared by July end.
Here is my badage: AWS Badge
Developer associate is Developer focused and its bit different than the solution architect exam. I found Developer associate exam harder than the Solution Architect, but YMMV.
So here are my tips and preparation topics:
You success in exam depends upon recognizing keywords in the questions. All answers may look similar but keywords will lead to right answer. Pay attention to words. For example: 'low cost', 'encryption at rest vs encryption in transit'.
Know how to do Read Capacity Units (RCU) and Write Capacity Units (WCU) calculations. You might get one or two questions on determining RCU/WCU. Don't forget to pay attention to strongly consistent/ Eventual consistent keyword in question.
Sometimes you may find answer to questions in other questions. While reviewing see if any other question has answer to it.
Use all the time available for the exam. If finished early, spend time in reviewing all questions.
Attempt as many mock exams you can. This will prepare you on time management and questions patterns. Questions will be verbose in real exam.
There could be command level questions like what this command do, when to use etc.
You need to understand the concepts very well and should have some hands on. It is easy to eliminate two answers.
Know CI/CD services like CodeDeploy, CodeBuild, CodeCommit. Understand BuildSpec and AppSpec difference. Code Deploy lifecycle hooks. CodeDeploy Deployment Types for Lambda, ECS and EC2.
Cloudformation, KMS, SQS, SNS, ECS, API gateway, IAM (Inline policies/ Managed Policies) and Lambda (Concurrent execution Limit,
DynamoDB. Local Secondary Index vs Global. DynamoDB Accelerator. DynamoDB Streams. SCAN vs Query.
Amazon S3, EC2, Elastic Beanstalk and its deployment types. Knows CORS.
CloudWatch, CloudTrail, App X-Ray
You might also get architecture level questions but not much.
Good Luck!