Originally posted by bcernucan Which one of these lenses are best for portraits?
50 F1.8 and 50-135 F2.8 will be your best bets. In particular the 50-135 is an excellent tool for portrait.
Originally posted by bcernucan Should I buy another one?
Only if you wish for a wider field of view, depending on the environment where you are shooting. If so, I'd look seriously at the DA40 Limited, or the FA43 Limited. I prefer the 43 but the 40 is maybe easier to approach, cheaper, and extremely good on APS-C.
If you want a faster tele lens, the FA77 is a no-brainer. It's my favourite portrait lens hands down. The only lens whose images I like more is the DFA*85mm, but it's much larger, heavier, and expensive. I don't recommend it unless you do more than experimenting and exploring.
The DA70 Limited would be another fine choice, I have less experience with it, I don't think it meets the level of magic of the 77.
Originally posted by bcernucan Any tips / links to tutorials for my level?
Look at images you like, then figure out how the light was used.
Learn to use light to your advantage. Off-camera flash, reflectors, modifiers, etc.
Look at David Hobby's Strobist site and videos. Grab a book by Peter McNally. Experiment!