I like the colour in this – very vibrant. The shallow DOF makes me concentrate on the person at front left and I follow their gaze ‘to the bottom of the frame’. You have created an ‘emotional line’ that leads me out of the frame. Maybe if you had use a portrait format we could have seen what the person was looking at and I think would connect us to the image more.
The thing about all photography is to learn as many styles of presentation as possible, shoot all the angles you can and see what works for you. It is just practise and you will start to automatically turn your camera without thinking.
I really like candid work. I think there is a bit more room for small issues that we wouldn't like in posed shots but same compositional issues remain. The guys head in the background is distracting and as Peter says we should probably see the subject that the person is looking at. But great to get out and start taking pictures of the real world! So keep at it!