How to build Two way Trust between windows2003 domain servers

i have created two different domain namely d1 and d2.Here iam able resolve domain d1 from d2, but not possible to resolve domain d2 from d1.so iam not able build two way trust from domain d1.iam able build two way trust from domain d2,but users are not able to login from both the domains.

plz kindly help to solve this issue.

senthil.