advice for a beginner

[l0ser]

Well, I got a sony a390 for christmas and I've been using it quite a bit.
Problem is there's still something that i cant understand, and out of all the pictures ive taken ive only liked about 3, would you guys be able to take a look at them and give me advice?

Flickr: alexnewman-'s Photostream
(using for an easy storage place )
There's the 3 photos I've taken, I know they're simple but they don't look terrible, well I don't think haha.
Anyway:
the problem I'm facing:
I have an 18-55mm lens and I can't get the aperture lower than 5.6! D:
can anyone give me advice/creative criticism on those pictures and help me with the aperture?

Thank you <3

 

[l0ser]

My bad, I've got it on 18 and it is on 3.5, thanks alot! )