i know this might sound a bit obvious but always plum your depth
here are some tips from a 14 year old
(if u don't know them already) :-)
try a boilie in the water if you are interested in catching a carp that is you've got to have a line in to get one :-)
try to fish with the lightest hooklength you can get away with needless to say really.
this is another obvious one but if your fishing with barbless hooks (which i do everytime) on the pole fish with the lightest elastic you can get away with
if you are fishing with barbless hooks but with a rod what I usually do is use a quivertip because with a rod with a quite stiff tip will put too much pressure on the fish because it will slip the hook either use  a quiver or a soft action tip rod
if you don't get a bite for a while and the venue you are fishing is a known pike water try casting a lure out a few time or even go full out piking with dead baits and all.
hopefully this will be you with all these tips :-))
or you could jump in like this fellow did hehehe and he found the problem
try to speak with local people aswel you can sometimes find out some useful hints and tips about the place you are going to fish