Where do I start if I want to learn custom modding an android device? I have some basic knowledge of android phones from a fan's point of view and have had a bit of experience with testing of custom ROMs but I really would like to start with basic development on my own. 

I'm no developer, which is why I need some serious advice of where do I start and how do I proceed. What kind of prerequisite knowledge do I require ?

Any kind of tutorial or knowledge database which can help me get started would be very helpful.
XDA is a good resource but not a good starting point. The AOSP is also. But the best idea is always to look how others are creating customs ROMs. For example the CM development for the Kindle Fire:

A good starting point is Jackpoint Calvin's post about how to create a CM update.zip for the Fire from source. It gives a good overview about how the kernel, ASOP, hardware modification and CM play together. And how these are handled with Android's repo script.

Forums are a good information resource, but it's hard to find useful information fast. IRC channels are the first place to get involved. Join a few rooms to get into contact with developers. Maybe you find a beginners task on which you can start working.

Also you need knowledge about Android/Linux kernels, hw drivers, C and some Java.