Shanghai, Nanjing, beijing

Huh, from Singapore? You must be joking.
Let me know if you want help with pre-buying the tickets, I'm studying in Shanghai.
Cheers!

oh okok...but how much does the soft seater( hmm not too sure bout the terms)costs? The Z trains dat's supposedly to be the most comfy ones eh

Soft seat? For what, Nanjing -- Beijing? You'd want a hard sleeper for that, if not a soft sleeper.
BTW, would appreciate if you could refrain from writing in "SMS language", thank you.
Cheers!

If you're going on the Shanghai -- Beijing Z trains, those only have soft seat and soft sleeper. I would advise you to take soft sleeper. Price is 478/499 RMB for upper/lower bunk.
Cheers!

Oh alright...thanks....but still contemplating whether taking a domestic flight from Nanking to beijing will be better chyoice or should i stick with trains....ive heard mixed reviews from both sides....guess taking a flight will be an option if i decided to make my stay in nanking slightly longer...anyway, how many hours beforehand do i need to be at the station b4 my train departs?

Well, who has been telling you to fly and who has been telling you to take the train? Think carefully about who is more similar to you as far as being a traveller goes. I personally would definitely take the train, much more time-efficient and cost-efficient.
BTW, in case you haven't noticed, I was offering to help you buy the train tickets. It's up to you to trust me or not.
Being at the train station 30-40 mins before time of departure is usually sufficient.
Cheers!

okok thanks for your offer...once i've confirmed with my travel buddy, i will contact you :)

Anyway this is my current itinerary...a tentatively one:

2nd july -6july in shanghai( most likely on 5july a daytrip to tongli)
6july morning taking a train ride to nanjing, explore around and spend a night there.
7july another day to explore, and taking a night train around 9plus overnight to Beijing
8july morning reach Beijing and stay till 13july noon
From there i will stopover at Bangkok and stay a couple of days before proceeding back to Singapore

I dont know is it enough to have just like 3 days in shanghai and 1 day in nanjing...and advices?

Too many days in Shanghai. I would suggest that you do an overnight trip to Hangzhou within those days.
The rest of your itinerary looks fine.
Cheers!

Oh...but im reaching shanghai 2july pretty late...say around 5ish pm or so...if an overnight trip to hangzhou, should i head to nanjing from there or back to shanghai again?

You should in that case go on the direct bus from Pudong airport to Hangzhou on 2/7. Then train Hangzhou -- Shanghai early morning 3/7. You then have 3/7 and 4/7 to spend in Shanghai, since you said you want a Tongli daytrip on 5/7.
Cheers!