I have received a rabbit snail, two golden Incas, and a nerite. I only have a 10 gallon tank and my parents will not allow me to get a filter for it. I am a first time keeper and very worried about maintaining the water conditions, especially since it is not recommended to keep these snails without a filter (and that's quite a few snails in one tank). Also rabbit snails are recommended to have a much larger tank. Hopefully I can soon add more live plants. I plan on weekly 40-50% water changes, avoiding over feeding, and gravel vacuuming almost nightly, but I don't believe this will be enough to keep ammonia/nitrite/nitrate under any control.
You need to find a way to get the surface water moving.
You can use an aquarium airpump and an airstone or simply use a fan to blow air over the surface of the water.
If you can limit the number of animals in your tank you will not need a dedicated filter in your tank; the surfaces on the plants and your tank will provide the bacteria a place to live and as long as you can keep the water moving, your tank will be fine.
You do not need to vacuum the gravel every day, it is better to do this as a part of your weekly water changes.
It had been best if you could get a filter up and running now, but you can add this later; until you do, try to limit the food you give each week.