Hi - 1st post so go easy on me!

Im just starting out playing online and having read plenty articles and strategies (particularly some very good ones here) i am trying hard to learn how to play properly rather than just messing about.

The main problems i am finding are:

- nearly all tables seem to have 1 or more aggressive player who tend to make raises where my pot odds dont justify calling. As they are aggressive sometimes i have called them when i have had position and thought they were bluffing, but have always got stung.

- When i have had premium hands 1/2 the table will fold pre flop, and everyone else tends to fold before much money is in the pot. I am trying not to bet too high so as not to scare people off, and dont think i am so tight people fold to every bet i make.

- 6 or 7 times tonight in an hours play i folded hands like J4os or 83os preflop without having to call more than the BB, not wanting to waste money and then the flop came and would have given me trips, or full houses or 2pair. Needless to say if i did go in with these type of hands nothing ever came.

Sorry for the long post, i really want to improve my game and play well so any advice would be much appreciated.

Thanks!