There is no best technique. All techniques have advantages and disadvantages depending on the dreamer and personal preference.

What technique is easiest also varies. Generally, DILD is easiest to learn. Anyone can do the techniques because for the most part all you have to do is remember to reality check often be more aware. WILD is much easier for people who already know what a lucid dream feels like so DILD is usually best to learn first. A lot of people have a hard time with WILD (myself included) while others get the hang of it quite quickly. WILD requires more actual practice and experience to master while DILD is more about breaking the habit of thinking you are awake.

WILD or variants of WILD like DEILD are more reliable than DILD. The thing about DILD is that there is always the chance that you won't think to RC while your dreaming. With WILD you yourself initiate the technique. As long as you choose to wake up and give it a try then you guarantee the possibility of a lucid every night.

Don't limit yourself to one technique though. Think of them like tools on your tool belt. You can use them all together to give you the best odds of getting a lucid dream. WILDers should still practice DILD techniques take the most advantage of the dreams. WBTB is required for WILD and helps DILD and dream recall immensely. MILD and mantras are fantastic and can help with DILD, remembering dreams, remember dream goals. etc. EILD and lucid aids are worth experimenting with but should not be relied on.

My first lucid was a DILD. I had been practicing for about a week. It started out in my room as if I had woken up in the middle of the night. I knew about false awakenings so I tried a reality check. I was quite surprised that I was actually still asleep. I have had only a few mediocre WILDs. I need to take more time to practice it. I usually get lazy and just go back to sleep.