I have been in this hobby since I was old enough to say the word train. In my time doing this, I have learned several things to help me enjoy the worlds greatest hobby better, especially when it comes time to build a layout. Now we are all different in this hobby and you will rarely find someone with the EXACT same tastes as you. When you are building are designing your new layout here are some things you need to consider.
This is the most important issue to cope with. It doesn't matter if you have $1 million dollars you can spend on your layout, if you only have a little 4'x6' corner that is your limit. The question here is how much space do you have that you can use? Do you have a little corner or an entire house at your disposal?
The size of the trains you pick should come in direct proportion to the amount of space you have. I have modeled in a lot of different scales, so I have equipment for just about everything. If you have A LOT of space available than just about any scale is ok. If you have less than 32 square feet available (4'x8'), I would highly recommend N or Z scales.
How much can you blow on this layout? Do you have less than $100, or more than $1 million. Money is a crucial factor as well.
Some people like to model one specific railroad, be it an actual prototype or a fictional line. Some people dont care and will run anything with anything (ex. 4-4-0 Americans with modern high cube boxcars). Dont be afraid to experiment to find out which of these your are.
Some people like ultra-realistic operation and follow prototype procedures BY THE BOOK! Some just like to sit back in a folding chair and watch thier trains run on the main. Again, experiment, do some research, and if you can ask local or fellow modelers.
Some people like the Iron Horses of the old west. While still others run only the most modern equipment. Others will, again, run anything with anything. If you do pick an era though (and stick with it, it will help elevate the level of enjoyment you will get out of this hobby. Also be sure to research your era you have chosen.
7.The most important thing is to keep it casual. Dont get too uptight or carried away. At that point it becomes an obsession, not a hobby.
This is a great hobby full of choices. I hope that this advice help you guys out. Happy railroading.
Lionel collector, stuck in an N scaler's modelling space.