I don't now what else you can check with out having pressure gauges. A/C repair is so temperamental, even a small leak and the system operates inefficiently.Autozone have some popular workshop manuals for free on line once you register (for free) on their website http://bit.ly/autozone_repair_info. There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online There are some good automotive air conditioning tutorials on line to get a good over view of how the whole air conditioning system works but for vehicle specific instructions you will need a workshop manual Alldats being the best and easiest to follow.
I've seen the condenser act as a "filter" and get blocked up with debris if the air conditioning compressor failed and spread debris through out the system. Cleaning/flushing the system during any repair is crucial.