As others have said.. distracting background could have been dropped out a bit with a wider aperture... or... and I'm surprised no one else has suggested it... go somewhere else? It's hard to tell at such low resolution, but it may be out of focus too.
Is it a portfolio shot? Not really. No offence, but it's just a snapshot of two people smiling at the camera that anyone could have taken. There's no evidence of craft skills, or creativity, so it's not something I'd be showing off.
Think of ways to make it more interesting. Interesting locations... using longer lenses and playing with depth of field. Using flash with daylight.... using off camera flash perhaps (I've no idea what your skill level is, so not sure what to suggest here). Avoid doing what anyone else would do.... which is have them stand there and smile at the camera. Think of how they are arranged in the shot.. do they have to stand next to one another? Why not move them apart front to back.. left to right... add depth... add space. Where people are in the frame is crucial. In the film industry, this is referred to as "blocking"... and it's one of the key things that make a shot.
Why not try and get shots where they are interacting with each other rather than just smiling at the camera? If you want a formal portrait, then to avoid the snapshot aesthetic, it will need far more craft skills with lighting, or just really fantastic natural light... and a great location.
Lighting! Great photography needs great lighting. What did you do to consider this with this shot? Again.. I really don't mean to cause offence... this is trying to help you... but I suspect you never gave it a second thought. It's a dull, uninspiring day with flat, uninspiring lighting.... which may be great if it fits the mood and sense of place... but I don't feel the formal, smiling at the camera vibe this image has is something that will ever be helped by flat grey lighting.
The image also has a very unpleasant green/yellow cast that is making their skin tones look a bit jaundiced.
You should be thinking about this stuff even if it is just an image for yourself, of your kids.
I take "snapshots" of my family all the time.. not everything I do is a art based project, or commercial work. I'm not suggesting everything that you take has to be a masterpiece, but I think portfolio shots should be something more aspirational than family snapshots... but that doesn't mean family snaps can't be interesting, given the right locations, lighting and treatments. Give them narrative, a sense of occasion... a story... a sense of place... something that can engage the viewer. Family and friends present opportunities for great images, but rarely do they provide portfolio material.... but they CAN create engaging, interesting images. Expression, atmosphere, place, emotion... all make for interesting stuff.
Here's some stuff... pretty much randomly chosen from my snapshot/family folders. I know posting your own images in a crit thread is poor form, but I'm not doing this to show off my skills at all. ALL of these images are flawed in many, many ways, and I'm not posting them here for crit either, but once you get used to recognising what makes an interesting image, then you start to automatically "see" the image right there, right then. No need for post processing or messing about either once you have technical skills well practised... perhaps a crop here and there is all that's needed. I get far more enjoyment out of looking back on images like this of my family than those where they're just smiling benignly at the camera. So here's some of my "snapshots".. no pretence at art... no pretence at being a wise ass published professional and academic... just snapshots of my family, warts 'n all. Interesting lighting, interesting expressions, emotions, locations.... it's about capturing the moment and deciding when to press the shutter... as a certain well known Frenchman once said
http://i.imgur.com/JRFgkwD.jpg
http://i.imgur.com/p1NpYFH.jpg
http://i.imgur.com/LxAq60E.jpg
http://i.imgur.com/UpbbicK.jpg
http://i.imgur.com/F35HpK9.jpg
http://i.imgur.com/BpeTgFN.jpg
http://i.imgur.com/hMyohpR.jpg
http://i.imgur.com/s5pUhQb.jpg
http://i.imgur.com/7etNx0x.jpg
If you want
portfolio shots, that's when you need to start PLANNING images.. preparing for them... lighting them beyond what's naturally available often as well... thinking of clothing, make-up... you're crafting... MAKING an image then. For informal stuff....concentrate of capturing great moments, with interesting framing, expressions, lighting, and moods and emotions to start with. Think beyond "say cheese". Maybe you like documentary, street style stuff... fine... you can't plan the actual shots, no.. but you you still need all of the above.
So start addressing stuff one thing at a time. Is the lighting flat and uninteresting? Maybe try using fill-in flash, or better still... just hold off on pressing the shutter and wait for more inspiring light. Look at the backgrounds... are they interesting, or distracting... do they help to tell the story, or do they add noise... think of depth of field and aperture use and how it can help. Framing... do people need to be central, off to one side... don't get too bogged down in that rule of thirds nonsense, but does the framing need to place the subjects bang in the middle?
I hope this helps. If photo bombing a thread is deemed inappropriate, Mods please delete this post. I feel it may give some insight however into how photos don't have to be technical masterpieces to be engaging and worthwhile.
Portfolio shots however.... they
SHOULD be masterpieces... that's the whole point of a portfolio.