First of all decide what pictures you want to display. Organise around themes ie. Family, holidays, weddings, kids, graduations etc. You may have frames already that are perfectly good but may not be the colour you like. This is very easy to fix. Go to your local hardware and get a tin of spay paint in white, cream, silver, gold etc. If you want the shabby chic/distressed look pick up a soft sandpaper when your there. If you are mixing frame sizes and style try to stay within a colour theme.
Here are some pictures that will give you ideas on the look you want to achieve.
Notice in this one a horizontal line going through the centre and pictures placed above and below.
Pictures on shelves is a great idea and allows you to update easily. Use a mixture of sizes and colours giving a more textured, layered look.
In this case the pictures are arranged starting at a centre point and working there way out.
If you want to add a splash of colour to your walls here are some lovely ideas.
Hope I have given you one or two ideas. Maybe you could post some pictures on FB of your own arrangements. Have a look on my site http://www.dressmyhome.ie/picture-frames.html for a selection of frames.
Until next time,