I would say DILD, through very frequent and proper reality testing. Write on a piece of paper "I will do a reality test whenever I..."

1. [fill in the blank]
2. [fill in the blank]
3. [fill in the blank]
etc.

You fill in the blanks with both things that happen in real life, as well as things that occur frequently in your dreams. So it might be...

1.) Whenever I am sitting with a group of people.
2.) Whenever I enter my bedroom.
3.) Whenever I see a cat.
4.) Whenever I feel a strong emotion.
etc. (I hope you get the picture.)

Try not to write too many of those tasks, so I would say 7 is an ideal number. Later you modify these tasks according to your dreamsigns. If you notice that you never enter your bedroom in a dream, then you will change that task and write something different.

Now, I say frequent and proper reality tests for a reason, and that's because you can do a reality check in a dream too fast, or without really questioning your state, and you will end up not becoming lucid. Also the best way to do a reality check in my experience is to combine two reality checks.

There is much to be said on this topic, but seeing how DILD and reality testing is discussed in thousands of threads on this forum as well as articles/tutorials, I think it's unnecessary to go into details.

I wish you good luck.