First, if you want non stock gadgets, look for mods.
I use MaGui and I am really, really pleased with it.
There are other mods around as well but I'm really only familiar with MaGui.
You also have the grand supermods, like GWX3, the one I use. Other supermods exist and I bet you others will chime in telling you more about those.
Pick the one you think will suit you the most.
Stock game is a bit, shall we say, limited in gadgets to help you plotting a shot, or even plotting an attack position.
As for targeting and shooting, there are plenty of different methods you can learn.
Here are two that, although they take a bit of studying (videos on youtube covering both methods), they work pretty good.
http://www.subsim.com/radioroom/showthread.php?t=225129
If you like maths, then there is a piece of beauty here
http://www.subsim.com/radioroom/showthread.php?t=200846
Good luck and do ask more questions as they pop up.