Hi!
Kinda new to the forum, wanted to share what certs I earned and how I studied. (It might be helpful)
These were taken 3 weeks apart.
92%, 98-349 MTA OS Fundamentals
85%, 98-366 MTA Network Fundamentals
98-349
Study time: 4 days
Time spent on test: 40-45 minutes, I tend to let the time run out while I review and think.
Read the book "Windows Operating System Fundamentals: MTA 98-349" ISBN-13 978-1118295274
I skimmed through it honestly, looking at terms and technologies I didn't know or haven't used much. Would not recommend skimming through it. I would suggest installing Windows 7 clean and upgrading and using the basic tools MS provides with it. Snipping tool, Windows Media Center, etc. Microsoft has pages dedicated to these tools and several others which give a short but good read on what they are and what they do.
Background: I've worked in an IT department for 4 years and currently work at an IT consulting business, for the last 3 years I've been using and administrating Windows 7.
98-366
Study time: 3 days
Time spent on test: Same as above.
Watched several CBT Nuggets training videos covering exam objectives and read few Wikipedia articles.
I went into the exam a bit presumptuous, thought it was going to be a bit easy, until I got to the second question.
After I left the testing center, I was thinking about questions I knew I got wrong and the answers it had. I realized some of the correct answers 30 minutes after the test! I think I might have been a bit too tired and maybe a little stressed. I would suggest reading a book geared toward the exam and studying VPN technologies and how they work. I studied subnets thinking I would run into several questions on it, I wasn't the best at understanding it. So I studied and finally grasped it, only to find it didn't ask one question on subnets. I'm sure questions are there for it, I just didn't get any. So, my suggestion on this would be to give yourself enough time to study and ensure you understand what the objectives list. So much hindsight, I wish I could've told myself this stuff a few weeks back. 

 Also, if you have a membership to a video training site, watch 
all the videos on the subject.
Background: Again, work experience, however, I didn't do much networking and when I did it was very basic stuff. I had gone to a trade school in the past for computer servicing and it covered networking. I also really like reading Wikipedia articles. 

Hope this helps some people and good luck!
P.s: Can't reiterate enough! Give yourself time to study for the exams, make sure you feel comfortable with what's listed in the objectives. I'm sure I would have score a bit higher if I gave myself more time.