Another way of saying "to pay close attention to"

The complete sentence goes:

"This is not a perfunctory guideline. (...) This is something you need to pay close attention to while you code."

Something in "to pay close attention to" is bugging me. Any suggestions on how I could improve it? Or does it sound ok as it is?

Edit: there have been some suggestions to use "focus on", which should work in most cases; however, in this particular case, I'm not saying that it should be the center of one's attention, rather something very important that needs to be checked constantly.

Be mindful of would probably work well in that case.

Otherwise, it does sound ok to say pay close attention.

Sadly becoming antiquated, but the verb attend is both adequate and more graceful than the compound pay attention.

E.g., in your example I prefer, "Attend closely to this while you code."

Other alternatives that omit pay:

• "Code only with close attention to this."
• "Code attentive to this."