Nice captures here. I agree, the third one shows a real moment that the newlyweds had shared. the only thing I can think of is on the cake, to me its an awkward perspective.
I agree, not bad for a first time. In the interest of constructive criticizim...
#1. Interesting perspective on the cake...but you are missing out on the top of each peice...and that's where the decorations are. We can sort of see some of it...but I think it would be better from above. I really like the use of side lighting...but it looks blown out in spots...and the detail is lost. It's crooked, that's easy to fix in post. The background is a bit busy...watch your backgrounds...or at least burn (or clone out) the lights in the back.
#2. Kids are great at weddings...and this cutie is no exception. Watch your backgrounds...this one is a bit distracting as well.
#3. Nice moment. Getting the rings and the certificate is a great idea. With this angle and shallow DOF...the certificate is not legible. Not that it has to be...but if you are going to include the whole thing in the frame...it would be nice to get it to be more prominent. Alternatively...you could have moved in closer and captures their rings and just a bit of the certificate...just enough to know what it is.
Hands are tough...they are not the most attractive parts of most people. It might make for a great shot if you asked them to take off the rings and shot just the rings, close up, on top of the certificate...or some flowers etc.
Again, pretty good for your first time. Do you have any more you would like to share?