Just a few thoughts on land.
- New mainland is a gamble. New sims look good and are cheap, but you can't predict what your neighbors will look like. You may find yourself selling again soon if the neighbors turn out to be bad builders or otherwise ugly. Large plots of new land are also a risk for being bought by busy clubs that will kill the sim with lag.
- Old mainland is usually expensive, but land prices right now give a good opportunity. The more stable older mainland sims can be very attractive, with features the new sims tend not to have and good looking oldbie builds. There is a much smaller risk of being next door to ugly if most of the land in your sim is not for sale. However, that also may keep you from expanding for prims if you need to. Visit the sim at different times of day to see the traffic level; if it is high and your computer is low spec, it may be too much lag.
- Make a firm commitment with yourself about tier. 15 dollars a month is plenty for a middle class home and 25 is plenty for a small mansion.
- Use the vertical, if you want to have enough room for at least a house and a skybox. To build over water (such as a boat) rezz it on the ground under the water and then hitch it up in edit. To connect all of your levels, use the freebie teleporters. Remember when you build to give some room for the swing of the camera. There are so many houses and types of furniture on sale for cheap that it's not necessary to build unless you want to, but building can be fun.
- Prims. If you house is low prim, you've got room for furniture. If your furniture is low prim, you've got room for plants and other pretty features. If you have bought or made an object that you just HAVE to rezz and it's primmy, consider getting an extra empty 512 in the sim to support it. Please put a few trees on that empty lot to pretty it up for your neighbors.
Enjoy!