any trick to buy from AliExpress without paying custom duty

No trick, I think you been charged because seller undervalued the product and your bad luck that it got caught. You should be thankful that it is not charged double. As in case of undervalue custom dept. Can impose 200% penalty.

its depend also custom officer. generally under $50 , customs didn’t apply except mobile phones or big parcel

That’s achhe din goodies for you, 41% customs for tech products. Pay it gladly. Believe that you’re paying it for the right cause.

Of course we didn’t need to pay exorbitant customs before 2014. It was totally free up to item value of 5k i believe, not 2.5k. Crossing that limit would need you to pay 14% customs, because that was the norm.

And no, you can’t do anything to avoid it. You can try ask the seller to under value the item, but if it’s caught during checking then they may impose fine on top of official custom rate, so you’ll end up paying more.

I always wondered up to what limit the custom is free! Your product’s real cost is what like 1.5k? So I’m pretty sure anything above 1k even then is charged! Much wow!

Purchase price doesn’t matter if they opened your package/decided to charge u (Couple of times i had to pay duty even for <1000 purchases but most of the times i got away with customs)
716 is the right duty for your product. They must’ve searched through AliExpress and found a result similar to this one
20$ – 1400+
45%+ GST = 700+
Thankfully it is (Customs) not based on MRP (Like How Amazon.com charges u)
Anyways if u can get to the Bangalore sub foreign post office u can counter them (If the customs charged is way too much) based on your CC/DC statement but it will only work if your purchase price matches the seller mentioned price. (If the difference is due to coupons used then it should be fine)  
Btw which courier?
I am expecting 6 packages from different carriers (11/11 sale purchases)..most of them are update-less after being sent from chennai sorting centre to Bangalore sub foreign post office

As @ithehappy mentioned, Customs have become very strict since 2014. Nearly all my phones/tabs were from Aliexpress till 2014-15 and I used to pay nominal customs of 5-10% which I was ok with but since 2015, Customs started charging abnormally and became very strict.

Had to pay 20k as customs for Mi Mix and then purchased a tab for which i had to pay 6k as customs whereas I used to pay hardly 1.5k as customs earlier (Purchased 3 tabs before 2014 and just one since). Last I purchased was Huawei Mate 20x and I had to shell 7k as Customs for that. Have stopped purchasing expensive items since.

Also, the packages loss frequency has increased considerably. Unless and until you buy thru Gati/Aliexpress shipping or premium services like Fedex/DHL, the package delivery percentage is less than 50% for me and I now feel that the price benefit is not worth the hassle considering the delivery time and probability of delivery.

PS: Having said that, have ordered 3 items during this sale with AliExpress shipping and as yet, none have reached India yet.

Any idea on china small packet post method of delivery ??