Getting help from your Neighbors and visiting them is an important facet of CastleVille. There are a variety of tasks that you can perform in their kingdoms (and that Neighbors can perform in yours). You are able to perform 5 Neighbor actions in one day. If you do all 5, you will receive a bonus of 25 coins. You can also receive Energy and Alchemist Powder in limited supplies when The most important of these are listed and described below:
When in your Neighbor's kingdom you are able to collect resources when they are ready, and taxes from their houses. Taxable houses in your Neighbors' kingdoms will reward you with 10% of the regular tax. Focus on the highest paying houses, such as Caravans and NPC Caravans, to reap the greatest rewards. Similarly, Royal Buildings will give you a variety of rewards that don't quite tally up with those of your own kingdom. They are one of the best things to attend in neighboring kingdoms, however.
Interacting with animals in the Neighbor's kingdom will give you a few coins and also speed up the animal process for your Neighbor by 10%. You can also use a Neighbor's Pond is one of the most effective tasks you can perform when visiting foreign kingdoms. This will give you all the rewards associated with the Pond, such as Sand, Shell, Bass and Water Pails. Flowers work in much the same way as the Pond - you can collect Beeswax and Honey from them. You can also tend to Roots, Ferns and Mushrooms to get Ogre's Belch and occasionally Berries.
If all that's not enough, chopping down Trees will give you the same reward as in your own kingdom - one or two wooden logs. Bear in mind that it is probably more effective to request these from friends as gifts. The same applies to mining Stone and Ores. You can collect these resources but you may find it easier to simply request them from friends rather than using your Energy up in this way.
You can also harvest your Neighbor's crops and defeat their Gloom Beasties in return for a small monetary reward.
It is a help to your Neighbors if you accelerate their farms and buildings. You can accelerate them by 10%, and this also rewards you with some coins.
Your Neighbors are also able to help (and hinder) your kingdom, with some tips on this below:
The first thing to bear in mind is that you can setup your kingdom so that you have to approve all Neighbor actions before they can take place. This prevents people from being able to destroy all your hard work with mischievous actions. However, once your kingdom gets to a certain size, this becomes very difficult to maintain.
It is a good idea to place signposts near items that you do not want your Neighbors interacting with. You may have systems in place that you do not want to be interrupted by them, for example.
Reputation is required for the purchase of certain buildings and items. Reputation itself is represented in CastleVille as a brightly-colored heart. The primary way to earn Reputation is to help your neighbors with completing tasks and interacting with objects in their own kingdoms.