Getting your comics signed

I dont think it really increases the value unless its something older like silver age maybe. I've also been told that signatures sometimes actually hinder the value. The problem with comics today is that they're so high in production that they arent and probably wont ever be worth big money.

When I go to a signing I usually just bring some of my favorites by that writer/artists or number 1's they've done and have them sign wherever they want which is usually the cover unless its a hardcover then I have them sign on either that back of the cover or the opening page.

I usually only bring enough that I can carry comfortably to signings. I actually find it rather annoying when people show up with tubs & short boxes full of stuff to have signed.... -_-

As has been said, signing doesn't necessarily increase value and can often DECREASE the value (considered no longer mint condition etc). However, if you come at if from the fan perspective, not the collector/investment perspective, getting creators to sign comics can be a lot of fun. It serves as an icebreaker, immediately helping to overcome any initial awkwardness, particularly if you are not planning on buying anything (or the creator isn't selling anything).

A story from TCAF (Toronto Comics Arts Festival) that really cemented this for me:
Two years ago, I brought the most recent issue of Sweet Tooth to be signed by Jeff Lemire. It was issue 33 - nothing particular special about the issue, just happened to be the one I was able to shove in my bag before heading out the door. Lemire was signing with José Villarrubia, the colourist. Villarrubia, who was in from Spain, hadn't actually seen the issue in print and they really hadn't talked about the outcome, so when Villarrubia got it in his hand to sign it, he went through the issue pretty much page by page and talked with Lemire about the process. They pretty much forgot I was there but it was amazing to see these two collaborators discussing their work.
I've had a bunch of really great interactions with creators and gotten to get a bunch of things signed. I care way more about the former than the latter.

As to where to get it signed - sometimes it depends on the art - is there a white or dark space that they can easily place their signature? is it a super glossy cover that won't take the ink? - some times it depends on who is signing it. Last year at TCAF, I brought an issue of Adventure Time for Ryan North to sign. He signed it on the cover and told me that the artists, Shelli Paroline & Braden Lamb were across the aisle in case I wanted them to sign it too. Of course, I did, so I went over and when they saw North's signature on the cover they had some funny banter about how writers don't give a crap where they sign and scrawl all over the artists' work.

Some creators (like Gail Simone) say they will sign as much as you want to bring. If no one else is waiting, go nuts. If there is a big demand, pick and choose which ones you want (1st issues, last issues, ones that are particularly important to you personally) and have them sign one or two.