Most people simply don't value photography. That's the challenge for the professional market - how to turn that attitude around.
YOU may feel like you're undervaluing your services but it's the CLIENT'S opinion that matters. So, the reality of the situation boils down to, is some money better than no money in the absence of a more profitable assignment? Now, some money might not be ideal but it stands a better chance of paying the mortgage than the 100% possibility of defaulting if you have no money.
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So whilst it would be nice to have a magic cure, mind-set or business plan to increase fees and charge the rates you value yourself at, the realities of supply and demand will always prevail and determine the price.
In my opinion the decisions that need to be made aren't about how to increase prices. Rather to come to terms with the reality of the situation and decide a) whether you can afford to/have no alternative than continue doing the job you enjoy/know for the money it can provide or b) get out and find a more profitable means of making a living. Sometimes the ideal solution of staying put and making more money just isn't possible.