It would help if you created a timeline for yourself and stuck to it when completing your project.
What does it refer to?
It would help if you created a timeline for yourself and stuck to it when completing your project.
What does it refer to?
This is similar to an extraposition in which a clause is moved to the end of the sentence in that "it" refers forward to "you creating a timeline for yourself and sticking to it when completing your project." But in moving it this way, the participle needs to become a finite clause "creating" → "... you create ..." (see discussion in comments)
You can rephrase, but you'll need some pro-form, or to lose the explicit condition:
Creating a timeline for yourself and sticking to it when completing your project would help you (if you did it).
The form with "it" is better, as it flows more naturally (the long phrase is put at the end)