The best way is to help in a supermarket or bringing papers around.
Look for places that are most likely to hire part-time help at minimum wage. Some of them are supermarkets, chain stores (Home Depot, Sam's Club, Costco, fast food places and restaurants, among others.) The best way to do it is to put on clean, unwrinkled clothing and a well groomed appearance. Like it or not, employers don't like tattoos, long ungroomed hair, untrimmed facial hair or dirty hands. A big turn-off is the use of non-standard English (except a foreign accent) and forget it if you use socially off-color words. It may not be hip but never use the word "ax" insead of "ask". Like it or not, using "ax" sounds uneducated. We rarely don't consider the fact that many "normal looking", well dressed and mannered people can't read. Employers watch to see if a candidate is faking it and you may be asked to read or fill out a job application on the spot. It also looks good if you carry your own pen in your pocket ready to do business. Talk to the highest rated person in the business when asking for a job, the one who doesn't need to ask a supervisor. Remember his name and title and write it down after you leave. If he/she says no, ask if you can leave your name and phone number (or a short resume) and it woulod be OK to inquire again in a month or so even if you aren't called. People quit and things change in an instant. When you see someone doing something you would like to do ask them how they got their jobs and if there are any openings they are aware of. Get ideas from employees you see in stores or other businesses. The people most likely to know where the jobs are (and to talk about it) are the ones already employed and in the labor force. The best asset there is the ability to make people (particularly the customers) like you. Smile when you shake hands and whenever it is appropriate, say hello to customers, ask if you can help even if it's not your job and think of little extra thinks you can do to make yourself valuable, such as offer to help other employees and clean up things if no one else is around. Casual remarks about your positive attutude will eventually filter back to management. And customers are aware of the value of a compliment. If they like you they often seek out the manager on the way out to give you a compliment. Also, smile and be just as considerate when you interview. Don't argue or try to add anything ("but....") if they say no. Use the opportunity to interrogate the hiring person about other opportunities or other people they know who might be helpful. Once you meet the basic qualifications, it's who you know not what you know that will get you employed and keep you there. Good luck.