How do I develop a better relationship with my boyfriend who is acting distance from me?

TALK TO HIM!

Find out why he's acting distant first and go from there. See what his point of view is and tell him your point of view.

Communication is key!

Well, not too much details to work with, but I agree to communicate with him.
Are you clingy? Did you fight? Is there something going on in his life? This doesn't really give much details.
But usually when a partner is distant it a for a reason.
They just don't wake up and decide to be distant, there has to be something going on.

Did you ask him what was going on?

What do you mean by distant from you??

Distant how?

Talk to him, communication can resolve 95% of all relationship problems.