When I first started building CI/CD pipelines, I thought it was just about automating deployments. I was wrong. After working with Jenkins, GitHub Actions, and GitLab CI — here are the real best practices I wish someone told me earlier. 1. Never Store Secrets in Your Pipeline Code The biggest mistake beginners make: # WRONG — never do this docker login -u admin -p mypassword123 # RIGHT — use environment variables docker login -u $DOCKER_USER -p $DOCKER_PASSWORD Use your CI tool's secret manager — Jenkins Credentials, GitHub Secrets, GitLab Variables. Always. 2. Fail Fast — Put Quick Checks First Order your pipeline stages like this: Lint → Unit Tests → Build → Integration Tests → Deploy Why? If your linting fails, there's no point building. Catch errors early, save time. 3. Always Build Immutable Artifacts Never deploy code directly. Always build a Docker image or artifact first: # Tag with commit SHA — not just "latest" docker build -t myapp: $GIT_COMMIT_SHA .…