Hello! I'd like to improve the Aural as I find the Aural part in G.8 exam is difficult. Also I 'd like to improve my ear-taining. Anyone know how to improve? How to practice by myself? Thank you!

Get hold of the "Aural training in practice" book + CD (it goes from grades 6-8) and work through all of the exercises.
Get your teacher to play cadences to you (record them if possible) and listen to them till you get the feel of the sound (or play them yourself, if you're a keyboard player).
Whether or not you are a pianist, get access to a keyboard and play chord progressions to yourself until you can feel what makes a particular cadence or modulation sound the way it does.
Practice sight reading at every opportunity.
Listen to classical music on the radio and make a point of thinking "that was an interrupted cadence" or "they've just modulated to the dominant" whenever you can spot one.
Hum along to the harmony (not the tune) whenever you hear choral music. Switch from alto/teno/bass voice (never mind if you have to sing up or down an octave for any of these).

That's probably enough to get you started...