I am not an FC but i play one on TV ... errr .. i have been playing eve a long time and have flown with alot of them: good, bad and ugly.
I am not sure if you want the full meal deal answer as it applies to high, low, null or just specifically RvB. I am going to make an assumption before carrying on into verbosity that you mean RvB.
scouting: Scouting always a good idea - knowing what your enemy is flying, what system they are in, how many in the ajoining systems, how many docked, how many active, and how close or far from gates, stations all makes the job of an FC easier. I dont think we scout enough in RvB .. cause scouting takes time .. and in some ways results in less action .. but my opinion is that without good scouting - and FC can find themselves getting nuked by the opposing fleet which does more to lower morale and leads to people logging off which means less fighting overall. So in the long run - although it might take longer i think it leads to better fights which in turn leads to more fights over time.
when, what for use scanner (and how do it properly)?
Three ways to scout (imho) eyeball, D-Scan, probes. There is sooo much info on each i wouldnt write it here, check out google for a website, like EvE-Uni for in depth explanations of D-Scan and Combat Probing .. in RvB we mostly use eyeballs .. non cloaky fast moving ship - warps to 200 off gate and sees the enemy and reports it on comms or chat. If they are good they will use D-Scan to get a nice little compact list of enemy names and ships, post that info into a webapp that in turns spits out a nice webpage with the info that you can link. There is a post in RvB forums about it .. i think it was Corniel's (sp?). D-Scan can be used from far away off grid.. but you dont see the enemies layout and if they have drones out etc.. Pros and Cons.
designated scouts (when? how much?)
Usually a FC will ask for a volounteer .. if they want scouts . some do and some dont. If no one volounteers someone gets volountold. In the nullsec alliances scouts are often predetermined and vetted before being allowed to scout. In RvB its anyone anytime. The thing that makes it easier is we are usually in 3-4 systems .. you know where people usually are .. and often the FCs are talking .. so there are already alot of variables off the table.
communication - if you have designated scouts and have separate communication channel with them, how you deal with multiple communication channels ?
We dont .. one channel. Limitation of EvE Voice. In Null it depends on the FC and the comms setup .. i have seen it used and not seen it. I think its better when the scout is on another comms line to the FC .. but thats me.
2) movement of fleet -
obviously you are not going shortest path to enemy fleet till you meat them.
Yes we do .. alot of the time. Scout "They on the Otela gate in Jos" FC "Align Jos - Warp - Jump on contact and hold cloak". We dont have alot of paths to take .. and depending on the fleet composition we might wander through Poinen - to Jos or to Leik .. Depends on variables .. who has more #s, what ship types we have and they have .. As with any fighting .. small or large, real war, boxing, pixel pew pew .. maneuvering until you have the advantage is a good thing .. but in RvB - its often about having a fight .. regardless of winning .. so just giving'er is sometimes the best MO .. sometimes.
what maneuvers are you doing on way to enemy and which in what case?
I am not 100% what you mean by maneuvers on the way .. usually its a matter of warping to a gate, jumping through and warping to the next one. But .. It usually goes like this .. "Fleet Align to X", "Fleet take this warp (and the FC fleet/wing/squad warps the whole group to the location". "Fleet Hold on gate" / or / "Fleet Jump on Contact" / or / "Fleet get on Optimals off of Gate" / or / "Fleet Jump on Contact and hold Cloak" / or / "Fleet Jump on Contact and align X". Sometimes fast ships are sent through first, sometimes bait, sometimes everyone .. sometimes no one .. so many variables.
where you are setting camps and why there?
Camps are usually camps in RvB .. there are station camps .. but they arnt popular or effective .. and usually not even fun. Camps are usually on the Liek gate in Jos, or the Otela gate in Jos. Usually at optimals .. somtimes hugging the gate. Again depends on ship types, fittings, optimals, support ships - composition of the enemy etc.. Best all learned by just doing it a bunch. Null is different as you can use bubbles, interdictors - and there are more cloaky stuff and people comming in from wormholes, people jumping in through cynos or cloaky cynos or god knows what.
jumping into enemy: pros? cons?
Pros - its fun .. if you think you have the edge it can catch them napping if they dont have a scout on the other side. If they are close in and you are close in fit ,.. then its good .. if they are range fit and you jump in and they are at optimal its bad. Again having knowledge of the enemy is good - scouting good .. ignorance bad. I prefer the going around if you can .. and then warping in on the enemy at range .. but sometimes .. jumping in and starting a chaotic fight in the middle of their gate camp is awesome.
jumping through gate or no?
You have to jump through gates.. dont get the question.
gates, as I understand they have different sizes and "size does matter"
I had no idea until i read Lady's response that there was a different size .. not sure if that "new" (post 2007) or if i am just ignorant .. i'll go with the later.