[Imp]

Scout units get no bonus for being scouts apart from do normaly com with plus 3 on exp mor. If you are lucky they may see fractionally better than other units but assume not. Foot scouts are harder to see as they are normally size 0 & scout vehicles size 2 are your best bet.
Requires a bit of practice but judge the point of contact & get there quickly unseen. Now generally either stay put or move very slowly seeing & being seen are modified by the units speed stationary being the best.
You can use individually on a hill but a MG or ATGM could probably do just as well, otherwise teams or working with other units so someone sees the firer. If they are the target probably to busy staying alive to see who shot.
Scout vehicles I tend to use more for finding the main thrust of the attack, looking more for vehicles if see infantry thats a bonus but its probably time to leave. Again rush ahead & park in cover on the edge of woods etc. They need a safe exit route but reduce weapon range with Y key or Op Filter & so long as they remain stationary & dont fire should be safe at distances over a KM from detection by vehicles. Stay as long as you dare & bug out.
There role is info gathering do not get them caught up in the fight unless it is a choice target. there aim is to make everybody elses job easier.
If you are doing recon at speed then you will be seen & may as well do recon in force with squads as they have more firepower & survivability.
The main thing is overwatch if you are detected & fired on several units should have eyes in the area, more eyes more chance of seeing who fired. Then pop smoke or let the other units return fire.
As Gila said try a search it has been covered to death, a bit like your scouts.