A good tip? "Lucky Chance" in the third at Pimlico....
Seriously, I worked 15 months in an auto repair center for a large dept. store chain while going to school full time. School 5 days a week and worked Saturday and Sunday during the school year then 20-30 hours a week in the Summer. Heat in the 90's to over 100 in a building with a metal roof and no air conditioning, doing tires and batteries virtually non-stop. In all that time I made maybe a TOTAL of $10 in tips if that much. Probably less.
I am not saying your job is (or is gong to be) easy, nor am I belittling you, but you get to work indoors, in air conditioning, your hands and fingernails aren't polluted with grease and dirt, your clothes don't get dissolved by battery acid, you aren't out in the rain driving cars in and out of service bays, you don't worry about exploding tires or falling cars (I saw a V-8 engine drop some 7 feet from a car which was up on a lift, and BOUNCE, landing about 8 feet away).
Virtually all minimum wage jobs suck in some way. Whoever you are working for thinks you should be working harder. The customers think of you as furniture if you are lucky and the as slaves if you aren't. If you get a good manager and a good crew to work with you are lucky. If everyone tolerates each other and works together you are fortunate. Odds are that will change, and usually for the worse. However bad it gets it can get worse, a lot worse. Eventually the manager will be doing the district manager so can relax and will hire anyone and then ignore what is happening in terms of employees. No gunshots? No bloodshed? A good day. And you end up working behind a counter in what may as well be a Middle-East border dispute with all the love that entails.. which is none.
Tips? Dude! As a firefighter I spent a night, with no food, in the cold on a high ridge, laying in loose dirt, around a burning downed snag, using it's heat to keep warm and felt lucky as can be to have that.
There are food service jobs where tips are expected, but that is usually in a full-service restaurant situation. Taco Bell, MacDonald's, Starbucks, and other similar hand-off-style fast food establishments are different, and I would think that, psychologically, the masses do not feel they are getting service- just handed their order. They come to you, you don't go to serve them, so expecting, or more accurately, depending on tips at such a job may not be realistic.
I guess I've been reading too much Raymond Chandler of late. Marlowe is rubbing off on me. "It was the kind of hot day behind the counter that would melt bread. I felt like the armpit of a too-big man wearing too much clothes, working way too hard at a job I hated."