You could have it signed and then get it cgc’ed. They do signature stuff in their gradings. I work in a comic shop though, and in my experience any added value from an autograph is negligible (especially if the signer is still alive). It’s probably a good idea to get a photo, though.
Sometimes getting your comic autographed by someone will lessen the value. if you have no proof that the person did sign it, like a certificate, chances are it will decrease the value. For example, you meet Jim Lee at a restaurant and you just happened to have your copy of Wild Cats #1 on hand, you get him to sign it, chances are the value of that comic just decreased. You have no proof that it was jim lee who signed it, even if you have a pic, sometimes that is not enough (photoshop reasons). If you go to comiccon and get it signed officially and they give you a certificate of authenticity, then that certificate would be enough to merit an increase in price.
Honestly, from experience, getting something signed is only for aesthetic value, i.e. stuff you want to keep. In my opinion If you have Iron Man 1, don’t get it signed. Just keep it in great condition and the value should be pretty high.