Simple advises:
1) Take meter taxi from Airport to D1
2) Book one hotel near Ben Thanh Market
(Little more ex but near everything u needs lol)
3) Nice food can try Takashimaya SC (Walking distance)
4) Nice beer R&R can go Pham Ngu Lao or Bui Vien (Pub Street)
5) A Reminder to bring your "Bao Ji Wan" there incase take wrong food
6) Prepaid sim card (18GB) Should not cost more than VND 200,000
7) Change your currency at SG Chinatown best too haha (Rate Higher)
8) Wana take photo with phone make sure dont stand too close to road (cases of tourist phone kana snatch off from robber bike)
9) GPS Map very important if u travel ard in HCMC alone.
10) Night club not advice to try especially lone Ranger
..... still many but cant recall liao haha
>>> Hopes these few tips do helps u , cheers