How can I make my own dog food?

There are many different meals you can make for your dog using regular groceries you would buy for yourself. From stews, to mini meat loaves (known as "puppy loaf".) There are also raw diets, which you can ask your vet about or do an internet search on. I personally follow a balanced diet for my dog, which is similar to- but not exactly the same- as a balanced diet for people. There is meat, vegetables, a little fruit, and a little grain (like rice) in each meal. Your vet can give you recipes, or you can do a search on the internet. I have found a recipe book that I use often for cooking meals for my dog, and it also has some treats. It is called " The Healthy Dog Cookbook" by Jonna Anne, Mary Strauss, and Shawn Messonnier. You can get this book here: https://www.amazon.com/Healthy-Dog-Co...11?ie=UTF8&qid=1489175737&sr=8-1&keywords=healthy+dog+cookbook

Beware that if you only feed your dog human grade ingredients without adding in the proper amount of nutrients (vitamins and minerals that dogs needs that are not naturally found in human diet) that your dog most likely will develop a nutritional deficiency which will eventually result in more expensive vet bills. It may be simpler to start with a high quality dog food as a base and then supplement by adding meats&veggies you prepare.

combine meats and veggies into a big pot and let them cook together

For new puppies or dogs that have not been on RAW I start them off slow. With mostly chopped or ground up food. A mix of ground turkey and ground beef is the base. Then a mix of veggies like broccoli or spinach and carrots and/or pumpkin, and things like yogurt or kefir, brewers yeast, turmeric, sardines, mackerel, eggs, and crushed egg shells. (It varies each time depending on what I pick up at the store and what might be on sale that month.) Then I mix 75% meat mix with about 25% veg mix in a ziploc bag, then top it with a few logs of frozen green tripe. When I serve it, I add a dollop of coconut oil, a splash of ACV and then also give a multi-vitamin and a probiotic treat each day.
When my puppies are old enough, they start eating bone-in chicken/turkey as well and about once a month they also get offal (heart/liver etc.) I have been feeding RAW for almost 5 years. For newbies, I suggest watching lots of videos and do your research before jumping right in. Your dog will thank you for it.
Also do what is comfortable for you and your dog. If you can't stand the site of blood, then stick with ground meat. If you are not okay with giving your dog chicken feet or necks, then don't. It gets easier the longer you feed it. :)