That's enough for now. The information presented should give you enough knowledge to boldly go forth into the swamp. I hope that these tutorials have at least shown you enough to encourage you to learn more on your own. And they hopefully have given you enough information and confidence to start you creating your own applications. There are whole bunches of widgets and topics we have not discussed, but this should get you rolling.
Please remember one thing. Most of the problems you encounter will be "stupid C problems": bad addresses, missing or incorrect parameters, failures to increment ac, forgetting to manage a widget, forgetting a necessary #include file, etc. The normal crap. X makes it a lot easier to create errors like that. Don't let it get you down.