Do your research and once you narrow it down, 100% call and ask fish and game. Every year with out fail, hunters get taken in Alaska by illegal guides and those with very poor F&G records / complaints. Always ask for a full disclosure from your guide. Ask for a list of prior clients and call them. On my registration there was a box to check if they are willing to be contacted by future clients so I always provided that information up front. And if every prior client have a glowing report again be leery. Not every client will be 100%, ask for that list too. If they are unwilling to provide, I would suggest go elsewhere. Look for red flags, didn't know the area (understand guides have permits for special areas but at times there is such a term as guiding blind which means the guide has no experience in that unit / area, its not a bad thing to guide blind , unsafe, will take the risk of something illegal even if so minor, meat care.
Be leery of those who offer high success and especially without proof from prior clients / F&G.
Make a list of questions before calling. Get answers and call again with additional questions. I prefer phone calls, you can get a better feel of client Vs email which are OK for general questions and info.
And don't forget to toke your guide, assistant guide and camp usually an apprentice guide who does most of the behind the scenes work to provide you with a superb hunt. Its say a lot about you to handshake the camp chore and give him a toke. Some just hand the owner or lead guide and let it be. If you were satisfied of course.
Be prepared yourself. Get up early. Do some chores around camp especially on weather days. Act like you want to be there even when things so south and they do.