Farhansa... some tips for buying on Aliexpress.
1) Try to buy from reputable sellers only
2) Pay attention to the order processing time, some sellers have a processing time of 10-15 days, avoid them. Good sellers ship the item within 3-4 days.
3) Don't buy products instantly, sometimes the same product you want can be bought for half the price from another seller. Use the advanced search to check the lowest price for the item you need
4) If you like something, don't buy it instantly, add it to your wishlist. You will get a discount on it within 24 hours
5) You can negotiate a lower price than the stated price with some sellers. Chat and bargain with them they can lower the price even more before you make the actual payment.
6) Always check feedback score for the product you are buying
7) Read product description carefully before placing order
8) When buying clothes, double check dimensions in cm or inches, Chinese sizes are usually smaller than International. An L size T-shirt might actually be an M size for you.
9) Don't expect a warranty even if the seller says so. If there is a problem with the product you ordered, the best time to claim a refund is before buyer protection runs out.
10) Be honest in your dealing. If the seller has refunded you for something that was not received within the stated time and you receive the order after you have got the refund, contact him and pay him for that item. I believe if you do good, good things will happen to you 
Happy shopping
