1. Buy when price is low. (usually occurs when a strong cards is over the half way point in a new blood pack)
2. when price rises over 10% sell. (i think 10% would be good )
Also, i think if you want to see good price checks on cards then go into your preferences, under market change ''In the Market list of deals, I would like to see'' Graphics. Then to day / week / month. Whatever
Im no expert, but these seem to be the basics.
If this isnt an option, complete solo missions and do atleast 1 fight in as many Daily tournies as possible
If you have the last version of the iPod app you can still get free credits and get more cash by getting packs. If you do not have it, then you can do what I do and just keep refreshing the market and buying cards that people sell at 10% lower than normal.
There is no easy way to make good amount of clintz fast and reliably, unless you count those offers that will give you the initial push. But they are one-time opportunity.
After that becomes this equation:
Clintz = Risk x Skillz x Time sacrificed x Effort
or using the shortcut
Clintz = real money spent
If there would be easy way, then everyone would do it. The easy way now is to play that one game in DT to cash in 50. Thats the best easy risk-free low-effort method you will find. Its will not make you rich quickly - but atleast its something.