Hi all.. thanks a lot for your comments and suggestions so far.. 
TerranRich: I try to give some light outline to the gate, but I'm not sure it's good enough, seems not very neat, or maybe my tracing is not very neat..
i'll improve it again..
Stochie: Yes, i'll add more object on it.. and i'll still looking for icicles references..
Scarab: I'm not so sure if the gold light you mentioned is refer to a sunshine.. but I try to put some sunshine light behind the gate, between the sky and the cloud at the behind..

Pls let me know which one need to improve more..
Thanks a lot..
mintymint

TerranRich: I try to give some light outline to the gate, but I'm not sure it's good enough, seems not very neat, or maybe my tracing is not very neat..

Stochie: Yes, i'll add more object on it.. and i'll still looking for icicles references..

Scarab: I'm not so sure if the gold light you mentioned is refer to a sunshine.. but I try to put some sunshine light behind the gate, between the sky and the cloud at the behind..

Pls let me know which one need to improve more..
Thanks a lot..

mintymint