/r/DIY might have something useful for you.

Fences start with post holes. You'll want an augur for this, which you can rent from Home Depot. You can also do this with an old fashion hole digger. You can buy these for not to much.

The spacing on things should be kept simple. Whole numbers like 8' across, 10' across type deal. Not 9 3/16'. You'll save your self a lot of trouble that way. Especially when you can buy prices cut to lengths like 8' and 10' already. I'll leave your spacing up to you though.

Start from a wall if you can, or an area that seems nice to start. Don't start your measurements from the middle of a fence section. You'll probably want a few friends throughout the entire building process. So starting from a wall, measure your intervals, again this is up to you, but something like 8', 10' or 12'. If you choose 10' for example make a mark with spray paint every 10'.

When you've got your permittee marked you'll want to get your holes. Choose an augur width that will allow for wiggle room, such as an 8" augur or 10" augur. This will give you a 16" hole or 20" hole respectively. Don't worry about auguring exactly, because your wiggle room will allow you to move the post once it's in the hole. But don't be terrible either. Start your augur on the spray paint mark.

A simple, rule of thumb for posts and post depth is 2/3-1/3. 1/3 being the actual hole depth. 8' post will have a 4' hole, 12' total post length. The height is up to you, but 8' is quite tall. Just an example I gave.

You'll want to measure your holes and make sure they are all about the same, again close but not perfect. Might be a nice idea to put some gravel at the bottom and compact it as much as you can. Just a few decently hard pounds will do the trick. Remember to dig a bit extra if your filling with gravel.