hi,
Timing closure is itself is a vast ocean. I guess u r a student, please go through " timing verification of ASICs " by Farzad Nekoogar.I Will definitely be able to help you out if you have some specific issues.
Do put some effort to go through this forum, u ll get plenty of materials.
With due respect,dear userz, please go through this forum before posting any queries, instead of vaguely posting a query,that IMHO reflects the amount of interest and dedication to gain and more importantly share knowledge.
Good Luck.