Finally, I was able to clear my CKAD certification with good 92% marks. Although passing is just 66% but these marks shows how seriously I have prepared for this certification because of it's practical nature as compared to the other certification exams.

Courses:
Udemy Course by Mumshad is very good and I think sufficient enough as it covers all the topics: https://www.udemy.com/course/certified-kubernetes-application-developer/

Mock Exam Series: (A must have)
I have purchase the mock exam series from the KodeKloud. https://kodekloud.com/lessons/certified-kubernetes-application-developer-mock-exam-series/

It's bit costly as compared to the course but it is a must have to boost the confidence for the exam.

A nice free source as well: https://killercoda.com/killer-shell-ckad
You can also use their free 1 hour sandbox environment for practice and reset it unlimited times.

TIPS:

1. Practice thoroughly after completing the theory.
2. It's confirmed that we get partial marks as well. When I got to know this it was a huge relief for me. Because, the Kodekloud labs only consider a question complete if all the sub-tasks are completed.
3. I spent good amount of time for one Month and completed theory twice before starting with the Mock exam series.
4. Just try to complete the labs as many times as you start to feel comfortable with the questions. Mock series will give you a much needed boost to schedule the exam.
5. Approach I usually follow - Go through one round of theory at a descent pace with proper discipline, it will give you an idea where do you stand and how much time it can take for you to get the certification.
6. Set the target then and start working on topics you feel you are weak. Try to refer different resources for those topics and prepare well.
7. Start with the Mock test series, it has 10 tests but halfway only you will start feeling comfortable then you can schedule your exam and go for a final sprint of few days.
8. I went through theory twice and Mock test series twice. This was enough for me to get the confidence to face the real exam.
9. Make good amount of use of free killer.sh shell mock exams. You get 2 session and each session has similar questions. My suggestion is to use only one and keep the another session for later on if you are unfortunate to clear in the first attempt.
10. Always use VIM setting in your practice exams so that you can easily memorise and setup that in your real exam. These VIM settings and alias are great helper in time saving as time is the key in this exam.
11. Don't stuck with the question, Flag it and keep moving. yes you get the flagging option and that is clearly visible how many questions you have flagged to revisit.
12. Vim settings I guess enough for the exam: (~/.vimrc)
    • set st=2 (preloaded)
    • set sw=2 (preloaded)
    • set expandtab (preloaded)
    • set ai (Auto Indentation)
    • set si (Smart Indentaton)
    • set ic (Ignore case in search)
    • set nu (Number line)
    • set ru (Ruler)
    • syntax on
    • set cursorline (I didn't find it that useful)
    • set cursorcolumn (I didn't find it that useful - but sometimes it is just give it a try)
13. Alias options you can set in bash profile: (~/.bashrc)
    • alias kn="kubectl config set-context --current -- namespace"
    • alias kf="kubectl create file -f"
    • alias kr="kubectl replace file -f"
    • alias kgp="kubectl get pod"
    • alias kga="kubectl get all"
    • export dr="--dry-run=client -oyaml"
    • export now="--force --grace-period=0"

Let me know in the comments if you have any specific question or need to discuss anything.

Happy Learning...