The last game I had which I sold was bringing me in around 1000/1200 on a 7 day basis.
The key to donations which has always worked for me is to not go over the top on donation packages and to limit how many packages are available.
Don't go adding 100 potions to a package just for more money, It's all in the quality of the package and the rarity of the items involved.
Example: If SET_ITEM is already readily available in the game and you then add it to a package it pretty much makes it useless in terms of marketing the donation.
Side note: When it comes to items don't go crazy, don't make "THE MOST POWERFUL SWORD IN THE GAME" because you then limit yourself for item progression in the future and clearly states that your game is just a Pay-to-win based game. Players HATE that.
I also made sure that donation packages themselves are items. I always allowed players to send/trade/sell the donation packages that they purchased.
If I remember correctly I had 3 packages (Small $3/Medium$8/Large$15) - a X-large was added on special events/holidays.
BELOW TAKEN FROM MY GAME FILES
Item: Donator Pack (S)
In exchange for supporting the game, this donator pack includes the following rewards;
Donation Status up to 30 days
A Donator Pack deposited into your inventory that will provide the benefits of the package you bought.
Donator Packs also include points that can either be used by yourself or sold in-game to another player.
You can buy multiple donator packs at the same time!
Your energy bar will refill faster!
You will receive 10 extra searches per day!
You will be granted access to a hidden tavern in town once a day for a special pick me up!
You can sell donator packs on the item market/auction market to other players for in-game currency!
I never ran BOGOS. (Just shows that you want money)
I could go on for hours about methods that worked for me over the years, on 2 different games.
At the end of the day it comes down to "why should I donate?"
I was heavily involved in my community at all times, I would always respond to messages even If my schedule was crazy.
I was active in the forums, I would run lots of polls within the community the gauge the feedback and opinions of those who play my game.
A lot of game owners don't realize that the game is a 24hr job, I would wake up through the night at 4am and log on for 20/30 minutes or so just to respond and reply to players.
This made sure that they knew I cared about the game and that I'm there to serve them in creating a better game and community for all involved.
ALSO, You may like to add a feature to your game but If the ones playing it don't care for said feature, you're not pleasing them at all.
Interact as much as possible, forums, polls, feedback, suggestions it all counts and makes a huge difference.
If you are in it for just cash then the game will likely NEVER succeed, do it because you enjoy it, you enjoy interacting with the community and just enjoy the experience.
I better stop there, I'm not even sure I said what I was supposed to say but anyway.