My best advice is Simple but Elegant!!!
I have done invites for a few weddings and the last one for my niece just about did me in, LOL. It was totally my own fault, since she is my one and only niece I wanted to make them extra special. I had a gatefold invite with a buckle of metallic silver c/s and on the buckle was an embossed in silver monogram. THe monogram was a stamp I had custom made. I also embossed a heart on the outside of the invitation. Ok that was just the outside of the invite! The inside was vellum printed iwth the words, and attached with double-sided satin silver ribbon to match the silver of the embossing and metallic c/s. Underneath that was a patterned paper and both were mounted on the inside of the card. I escaped pulling my hair out by doing very simple RSVPs!! But they were very beautiful.
I had a lot of fun doing up the prototypes, I unfortunately had no idea how long it would REALLY take to do them all up. I had about 75 to do and in hindsight I would have cut a few steps down or even out to achieve the same or similar look.
So in summary:
1. Do the prototype and make a list of all the steps it took to make that one. Write it all down step by step and number it. Add up all the materials to make it.
2. Double-faced satin is a dream to touch but a bear to cut and have it cut straight. Highly recommend organdy instead!!!
3. If you love heat embossing, go for it. It is one of the things that truly makes a wedding invite look beautiful in silver or gold. HOwever space out your time doing it over a few days. Trust me!!!
4. Make sure you invest in a good adhesive. I got rolls of Scotch double-sided tape and got the tape dispenser that sits on your desk. It attaches very well. Some people use tape runners. Whatever you use it HAS to stay well. Make sure you test that out before you do 100 and have them fall apart. Do NOT use glue stick!!!
5. Get a couple refill blades for your paper cutter. If you are cutting vellum you want a clean edge. Keep one reserved for just that, i.e. don't cut a bunch of SU c/s and then cut into your vellum, you will get a raggedy edge if it is worn down from the thick c/s.
6. Make sure you have all your envelopes figured out. Inside env, outside env., response env. Make sure only the outside envy gets a return address on it, the inside envy does NOT (it gets hand written on and can be lined) and the RSPV envy can be preprinted which I also did.
Have fun with it! I love doing wedding invites but I like to plan at least 2 months to get them done. Oh and make sure you have ALL the info confirmed with them before you do EVERYTHING. Sitting down to do invites, make SURE all is signed off. Doing RSVP, make SURE the address you are having them sent to is correct. DOuble check and never assume!
Edited to add that I really liked the envelopment ideas here:
http://www.mygatsby.com/
Wedding Invitation Wisdom Needed
