Which settings for a portrait?

[Mad Aussie]

Closest thing I have to what I believe is portrait caliber glass is a 50mm f 1:4 lens

I really like my little 50mm 1.8 for portrait if I have room to move. It creates a nice DOF.

[Marko]

I've shot plenty of (somewhat unusual)portraits with a 24mm...
You can use whatever you want.... you do get more reach with a non full frame camera due to the crop factor.

For me though, 50mm is short for portraits (not street photography...formal or semiformal portraits) even on a non full frame. 85mm+ seems right to me.
You may consider a decent zoom that covers that range.

At the end of the day though it really depends how serious you want to get. If you are just dabbling...then use what you have. It will work just fine ...you'll just need to get closer to your subject

[pop123]

Kat's advice is spot on. To that which she has mentioned, I'll add: Shoot at her eye level rather that up at her; find a plain background, a medium or darker tone to contrast her hair and skin, crop more tightly on her head and shoulders, and avoid cropping little bits of body parts (in this case the upper portion of her left arm). Bold crops are fine, provided they don't bisect a joint, but little bits tend to give the impression of careless composition.
Canon EF-S 18-135MM F/3.5-5.6 IS AF