How to get the general population to pay more in transaction fees? When mining becomes less profitable* what options are there for miners and mining pools to persuade or insist that end users pay more in transaction fees?

I'm interested in 


Specific code changes that need to be done in miners (to exclude low fee Tx)
Business plans (or description thereof)
Incentives of various types (..free Namecoins if pool X processes your Tx)


Sure there will probably always be miners who accept zero fee Tx but I am thinking that this might become the minority over time.  As a result these zero fee miners will finish fewer blocks and will cause zero fee Tx to be delayed before being added to a block.

*Mining can become less profitable for a number of reasons: increased difficulty, poor conversion rates, decreased reward, higher costs (hardware, electricity), or government regulation &amp; taxation on mining income.
I don't think that it is definitely a good idea to increase the transaction fee.  One of bitcoins biggest selling points is the ability for micro-payments and very low transaction fees.  While I do agree with others that micro-transactions will eventually move off the blockchain.  For now even with the block-reward halving, transactions fees still won't benefit miners financially much for a very long time.  As again as I said the ability to make bitcoin transactions much cheaper than traditional means is one of bitcoins main selling points and will be for a long time.  Until such a date that the majority of bitcoin transactions are made off the blockchain.  Instead in house by larger bitcoin payment and services provider outlets.