Any tips to train or teach my LO to sit up by himself. He is 6 months but still can't really sit properly unless he get support from me or my Wife. Thanks!!!

Actually, there is no need to teach LO. They will be able learn themselves at their own pace. Give LO sometime. At 6 months old ny boy faced a similar situation as yours. After a while, it passed. Its just a stage. Hang On! http://www.parents.com/baby/development/physical/stages-of-sitting/ Hooe this helps.