1 – Make sure you have clearly explained to your sound eng. that apart from recording mixing and packaging the mp3 as per your guidelines with proper intro and outro, he is also responsible for uploading the mp3 chapter by chapter and then waiting for any instructions from the audio team of acx.com in case of changes making the changes as per the instructions and making sure the audiobook has gone live and is actively selling on audible.com and iTunes. This is the last but most crucial step, most audio eng. just give the package of the audiobook on we transfer file and think their job is done but it is not. They have to make it live with all the corrections and make sure the deal you negotiate with them covers this last mile or critical task of making the audiobook active for sale. If not done your budget will go up as the Eng. will charge you some more for corrections and final upload.
2 – Make sure the voice artist is negotiated with and paid per hour basis and records at least 4 hours in a day. Rs 500 to Rs 800 per hour is a fair rate to give the artist.