To add to the excellent responses above...
Yes, for retail / food service, walk-in is perfectly fine, and a better way to make an impression than an online application, unless they specifically ask for the latter, in which case you might wonder if that's the type of place you want to work at.
* Learn as much as you can about the company - its history, local history, community events they've participated in or sponsored recently. Show that you are able to fit in just fine, since when an employer is faced with multiple suitable candidates, they're often going to pick the one they think is the "best fit."
* Show up during an off peak time (for restaurants, if they don't close mid-day, 2 PM may be a good time) with 3 copies of your resume and cover letter, and dressed for an interview.
* Ask to speak to the manager, and be prepared to do an interview on the spot.
- The reason why I suggested 3 copies of your resume and cover letter is that they may choose a 2 person interview - a manager and someone else (such as a senior staff member), in which case they can each have a copy to look at while you have one to refer to yourself.
- If they offer to schedule an interview later, great!
- If the manager offers to take a resume and cover letter and contact you later, then sure, provide a copy of each, then confirm their name and follow up in a few days.
* If the manager's not in, you have a couple options, and which one to pick is really situation:
- If a shift supervisor or assistant manager offers to take a resume and cover letter, do so, while asking for the manager's name so you can follow up in a few days.
- Otherwise, get the manager's name and if possible, ask the staff member about their potential availability in the next couple of days and come back.
- Remember the name and position of the person you gave your resume to so you can reference that.
* One common question is "why do you want to work for us?"
This is your opportunity to provide an answer (and cover this in the cover letter / email as well) where you can stand out. It's okay to say who like small businesses, but we can do better.
A potential answer might be:
The first time I remember coming to Dot's Diner was when I was six, and my grandma brought me here for lunch when she was visiting. I have fond memories of this diner, and I'm sure many others have as well since it opened in 1960. I would love to have the opportunity to work here, so that I too could help create such warm memories for others.
* Another common question is "where do you see yourself in (period of time)?"
This is one of those where you want to understand the organization and know some of the other positions you could potentially move into.
A potential answer might be:
I like working with people, and sharing what I've learned with others. I'd like to think that perhaps in two years I might be a shift supervisor, continuing to provide my best service to our customers on a daily basis, while helping the manager with administrative duties like scheduling and event booking and planning.
* Watch out for the random questions. I don't know why but some people like total oddball questions like "if you were a fruit, what would you be and why?" Autistics in particular tend to struggle with such open-ended questions, so please please be prepared and try not to get smacked by something out of left field.
A potential answer might be:
I would be an apple as an apple a day keeps the doctor away, and so I help keep people healthy!
I'm a former job search coach and while it's been some time since I've been in the field, I'm happy to provide guidance where I can.