Hi. I´m looking for some cards to compliment my Martel deck. I have found I got enought character removals but no attachments or locations, and I find it hard to play around some of those. Any suggestions?

Martell handles Attachments very poorly, Maester of Lemonwood, who only hits Conditions, is about the only in-House option.  I suppose you could run Let My Porridge Fly but that wastes a whole Plot for Attachment control you might not even need.  Given their abundance of I icons, Condemned by the Council is your Location control.  If thats not enough or if you have too many Events already you can try Pyromancer's Apprentice, but they arent all that reliable.

1. Nightmares for attachments on Maesters if your opponent decides to put one of Chains on Maester before giving him extra Maester trait through Apprentice Collar. This card will be also good in general against various cards you decide to blank. So it's rarely a completely dead card.

Another thing about Nightmares is that when you blank attachment attached to anything but Character, it falls of completely.

2. Ill Tidings if you have enough Maesters in your deck of which you will probably have at least 3 (Refugees of the Citadel) and probably a few others.

Good thing about Ill Tidings is that it's one of few cards that can consistently target Black/White Raven (the other one being Carrion Bird)