Here are some useful articles for SCCM troubleshooting:
SCCM Issues by Category:
http://arnavsharma.net/system-centre–more/basic-sccm-troubleshooting-made-easy
PXE Boot:
http://blog.jocha.se/tech/sccm-2012-troubleshooting-pxe
How to read SCCM log files:
https://www.swc.com/blog/microsoft-system-center/sccm-troubleshooting-101-log-files
SCCM basic errors:
https://prajwaldesai.com/sccm/sccm-troubleshooting/
SCCM log locations:
https://technet.microsoft.com/en-in/library/hh427342.aspx
SCCM Software Update Issues:
http://eskonr.com/2015/04/sccm-2012-troubleshoot-client-software-update-issues/