Start by reading these two bash scripting guides:
Bash beginners guide
Advanced bash scripting guide
Then set yourself a task. Take something that you do repeatedly, which has more that one step, but is a bit tedious. A script will relieve you of that tedium by allowing you to complete the task with one step: running the script.
You have you your home directory a number of caches: browser cache, thumbnails, etc. which will continue to accumulate files until you clean them out. A simple script to cd from directory to directory to rm the files will save you some time.
Then increase the complexity. Add a function to check the directory to see if it's empty before running the rm command. If empty, bypass the command, otherwise run rm to remove the files.
Scripts save time when doing *housekeeping* chores, but can do much more. Just look at the scripts in /etc/init.d.