If I had to purchase clothes and shoes for a particular job, where would I enter this information? And do I need my receipts?

You would enter those expenses as non-reimbursed employee expenses on form 2106.  This is then pulled into Schedule A, Itemized Deductions, in the Misc section subject to a 2% of Adjusted Gross Income threshold.

Form 2106 (Employee Business Expenses) is used for employees' unreimbursed travel, meal, entertainment, and transportation expenses (including DOT per diem). Form 2106-EZ is a simplified version.

Tip: In most cases, the IRS won't let employees deduct commuting costs. More info

Here's where to enter your job-related expenses:

1. Open (continue) your return in TurboTax if it's not already open.
   • Online versions: Make sure you've selected the Take me to my return button.
2. In TurboTax, search for 2106 and then select the "Jump to" link in the search results.
3. At the Tell us about the occupation you have expenses for screen, enter your occupation, then select Continue.
   • If you land on the Job-Related Expenses Summary screen, you can select Add Another Occupation (to add another 2106), Edit (for an existing 2106), or Delete.
4. Follow the onscreen instructions.