Reddit reviews The Raga Guide: Survey of 74 Hindustani Ragas

Disclaimer: Long answer, and quite subjective - I have no formal training of any sort (hindustani or western), I play guitar/flute/piano by ear and try to listen to most forms of music actively, and have consequently picked up a smattering of knowledge that is barely structured. If you want to really get into this, I recommend searching for a guru(teacher) - when it comes to Hindustani Classical, there's no real replacement.

1. Jhala:
   For a better idea of what the chikari strings do during a jhala, try this performance, pt.1 & pt 2 by Pandit Brij Bhushan Kabra (the jhala starts being apparent in the second half of pt 1 I think). The raag is Bihag. For the technique itself in the context of a sitar, see this.
   
   
2. Raagas:
   For a quickfire introduction to ragas, I'd recommend this 4 CD pack which comes with a surface level explanation for each of the 74 ragas - the basic notes that make up the raga, the time at which it is to be played/listened to and so on. Another thing I've done over the years is listened to more of Dhrupad as opposed to Khayal (which is what has been more popular over the years) - Dhrupad is stricter in terms of musical grammar, and consequently makes ragas easier to identify. As an added bonus the development of ragas is much slower, and it's a good introduction to microtonal variations in hindustani classical. In the same vein, listening to thumris (semiclassical in a sense) will help you relate ragas to their place in popular music.
   
   
3. Basic Theory:
   Finally, this playlist of short lessons aimed at introducing the untrained listener to the basic theory/philosophy of Indian music is great - it starts off with the assumption that you have zero knowledge of Hindustani Classical (or any music) and provides good insight into the workings and vocabulary of the music. Ideally start with this before you listen to the 4CD pack - it'll make much more sense that way.

Raga Guide is worth a gander.