that first one looks really nice, meh thinks my advice worked a bit =P nice job on it,
the second one is ok i guess, but i dont really find those colors matching
the last one has to much pixel on it i dont find that lookin so nice
anyway i can see that you didnt use gaussian blur which acctually can give a really nice effect (try using ur sigs for this one)
Merge all layers together
go to filter > blur(or sumthing, since i have the dutch version) > gaussian blur
set it on 2,5 or 3
then go to edit > fade guassian blur
set it on 100% (or lower, if u dont want the effect seen to much)
mess around with the blending settings, i most of the times use lighten, or linear burn, color burn, linear dodge or color dodge
just mess arround with all those settings, sometimes u can even try to combine 2 different sigs and make a new nice one with blending modes =D
(like mine, these are 3 different sigs in eachother, doesnt look TOO nice, but i like it =P)
**edit**
for ur first raziel sig, try using Color burn for a very dark mystirious sig, or try lighten for a lighter more fairy like sig >.<