Here is a file borrowed from Dan McIntosh that gives useful linux commands linux basics (pdf)
Here is a file with some tips on how to display and examine images with IRAF primer (pdf)
Finally, here are some useful links
Cosmology Calculator: http://www.astro.ucla.edu/~wright/CosmoCalc.html
Distance Measures in Cosmology (David Hogg): http://xxx.lanl.gov/abs/astro-ph/9905116
To access published journal articles use the ADS query: http://adsabs.harvard.edu/abstract_service.html.
For those people with Macs this link is useful http://www.janerigby.net/JRR/osx.html to get your Mac set up for Astronomy.
Many tips for using python are found by googling “Python Astronomers”
Get in the habit of reading newly released papers every day. These can be accessed at http://xxx.lanl.gov/archive/astro-ph. You should get in the habit of reading the “new” postings every day. Papers can be downloaded and archived very nicely using your favorite means. I like to use the “Papers” program from mekentosj.com
You should get in the habit of keeping a log of everything you do. I like electronic logs because you can search them and attach plots but everyone needs to find their own method. I use the “Notebook” software but “Evernote” is free and is also supposed to be good.