Ben pretty well covered it in his post - it is tough to predict. Every charter is going to be different. Some charters charge different rates and that will also be a factor in the tip calculation. Some days you get great tips, and some days you will work your ass off (cold weather, rough lake, hot weather, tangles, throwbacks, junk fish, more tangles) and the crew will hand you $20 - times like that it almost seems like an insult. There are great days and rough days. I've made some really great memories as a first mate, and made great friends as well. I fished with an 87 year old Korean war vet, on an 18°F April morning, in 4-6 footers., but it was warmed us both up netting his >8lb walleyes.

Also, and I know the walleye fishing is hot lately, but when it's not.. it can make for some long days. The first mate is there well before the crew arrives, to prep the boat. After a day of fishing, you'll display the fish for pictures and socialize, before scrubbing/cleaning/organizing the boat, cooler, etc. By the time you get that stuff done it can easily be a 10-12 hour day, and you need to shower, call your lady, sleep, wake up, pack your lunch and do it over again. It can be a grind. Then again, just as easily, you can be back at the dock at 9:30am with all of the boat clean up done, and nothing to do for the rest of the day.