Are you asking live or online? Well, for online the easiest thing you can do is get a program like poker tracker 2, then watch some tutorial videos on how to use the program, what the stats mean and some ways to exploit players with different stats. If we are talking about live I highly recommend "caro's book of poker tells
." Some basic tells that you may find helpful right away are:
-Players who are staring you down are more likely to be weak then players who are not paying attention to you.
-If a player is staring at the flop for a long time it is likely that he is weak.
-If a player glances at his stack right after seeing a card or looking at his hand he is strong.
-A player who checks his whole cards when the third of a suit comes out is more likely to have a FD then a made flush.
-Shaking hands mean strong hands. Unless the persons hands always shake then it is something else and should be ignored.
As to the first part of your question about finding it hard to fold strong hands, you may find it helpful to try playing mixed games for a bit, as the avrg winning hands in Seven Card Stud or Omaha are a lot higher then in holdem, this will quickly teach you to fold TPTK or you will go broke.
Lastly something to think about. If you are only playing strong PF hands then your opponents will catch on to this really fast and they will start bluffing
you on boards that don't hit premium hands well and will fold to you on boards that have aces and kings as those hit a lot of your range.
Good luck and have fun.