What procs are easy to learn and essential for SAS programming? I have learned several like proc print, sort, freq, format, univariate, anova, glm, import, transpose. What ones should I learn next?
Welcome to Stack Overflow (and SAS). The procedures that AlanC mention are all important.
Probably your best bet is to pick up a copy of The little SAS book and learn the data processing as well as the analysis procedures. I have used many versions of it for years and students like it. SAS changes at a glacial pace. So, if money is tight, pick up an older edition.
You have already hit many of the main procedures. Focus on data processing with data step and PROC SQL. SQL is its own language and is extremely useful with or without SAS. Also do not neglect ODS. SAS can make very beautiful output and the aesthetics matter when you are showing your portfolio.
If you want to be a professional SAS programmer you will need to learn macro, to automate tasks, and also the intermediate to advanced magic that Ron Cody writes about. Get comfortable with the language then work on converting your code into macro. Along the way be sure to check Cody's data cleaning book