I wrote a little preliminary guide for FarmVille that can be found on a separate Page on this site. Pages are displayed as Tabs above any Post. The following are nothing more than random Tips for beginners and veterans alike.
Purchasing Premium Trees:
Trees can be obtained in a number of ways in FarmVille. They can be grown from 'Mystery Seedlings' that can be obtained when you Harvest one of your own Orchards or found on Wall Posts from Friends who play the game. A few Trees can be obtained as Free Gifts from Neighbours. For the most part, however, new varieties of Trees must be purchased from the Marketplace using FC.
Premium Items of any kind tend to be time-restricted. You have a set number of days in which to purchase any Premium Item. Sometimes, a Premium Item displayed in the Marketplace is a Reward Item for completing a Quest. It is a good idea to go to a site like FarmVille Freak to see what all the current Reward Items for Quests are before you purchase a special Tree or Animal that is offered for sale. You then can decide whether or not you wish to go through all the Quest sequences required in order to win it or whether you would prefer to buy it outright. In many cases, however, Quest Rewards are NOT offered for sale. The only way to obtain one is by completing the necessary Quest.
Whenever you look at Trees in the Marketplace, you will see a tiny message declaring that the Tree either is Lv. 1 or Lv. 2. This message can be quite important as Lv. 1 Trees CANNOT BE GROWN FROM MYSTERY SEEDLINGS, nor obtained in any fashion other than by purchasing them from the Marketplace. If, therefore, you see a Level 1 Tree that you really like, you should buy it!
There are two types of Level 1 Trees, however. One is the Tree that, when harvested, creates a Mystery Seedling that will grow into a Big or Giant Tree of the same variety. For example, a Mystery Seedling obtained from the 'Spooky Crystal Tree' will grow into a 'Big Spooky Crystal Tree'. These Big or Giant Trees are Level 2 Trees. In fact, any Tree grown from a Mystery Seedling will be a Level 2 Tree. The Big or Giant variety of any Tree is very much like the original Level 1 Tree. You therefore need not purchase the original Tree if you have Neighbours who have that Tree and are willing to share one with you when they obtain a Level 2 Tree from a Mystery Seedling.
The other sort of Level 1 Tree is the one you should purchase if you really love it. This sort is unique. When it produces a Mystery Seedling, that Seedling will grow into an entirely different variety of Tree from its parent. A current Premium Tree of this type in the Marketplace is the Pinecone Tree. The Pinecone Tree, when placed in an Orchard and harvested, will produce Mystery Seedlings that grow into an Acorn Tree. If, therefore, you do not purchase the Pinecone Tree, you will not obtain one from any Neighbour's Wall Post. If you do purchase one, you cannot grow any more of them. You can grow only Acorn Trees.
Finally, there are some special Trees that can be unlocked by Mastery of other Trees. These include the Astrological Trees.
Activating Quest Sequences:
This is a situation that I have experienced myself and therefore feel that the 'fix' may be useful to other Farmers. It can occur at two points in time. The first point when it can occur is when a new Quest Sequence is released. You may find that other Farmers are able to activate the Quest Sequence but that you are not able to do so. In this case, TRAVEL. For example, a new sequence of Haunted Hollow Quests may not activate when you load the game on the Haunted Hollow Farm. Travel to another Farm and then return to the Haunted Hollow to activate the Quest sequence.
The second point when you may experience the same problem is when you complete a Quest Sequence and opt to go through the Quests a second time. Again, if the Quest sequence does not begin, TRAVEL to a different farm and then return to the Haunted Hollow to activate the first Quest in the sequence again.
This problem arises evidently only on NEW Farms that are linked specifically to any Quest Sequence. It is easy enough to circumvent in the manner described.