Some players develop a strategy for occasionally showing cards to give specific information, but initially the best thing you can do is never show your cards when you've lost - it gives information to your opponents about what starting hands you play, and how you play particular hands, which you don't need to give them otherwise.
If you aren't particularly familiar with blinds, showing cards, etc, then I would recommend playing on the play money tables until you can beat them, or play on
freerolls until you get good enough to win some starting
bankroll on there - until you can beat the Play Money tables you're very likely to lose money on average at
real money games.
What you need to do to become a winning player on average is firstly to become familiar with the whole structure of poker - the blinds, betting, differences between Limit and No Limit,
poker hands, etc. You also need to become familiar with the chances of improving a hand, pot
odds and implied odds (which isn't too scary after a little study), so you know when you're getting the right money to play, plus bankroll management, avoiding tilt, table selection, etc. Also, you need to work on starting hands (and why they're played - e.g. why AK is much stronger than something like A9), trying to work out how your opponents play (and how to respond to their style), how to spot the really bad players, and all the other facets.
You also need to think about whether you play poker mainly for fun or are serious about playing for profit. Some of the most consistently profitable games or styles of play aren't as exciting as mixing it up in most hands, but you'll be a lot more likely to make money off them. Patience and discipline are key to doing well. Also, many people like to have a game after a drink, and if you're serious about trying to build a profit, you don't want to drink and gamble, generally.
I'm not trying to put you off trying to play poker properly - most of the regulars here play 'seriously' but clearly enjoy the game still. I play with the aim of making a profit (all my poker bankroll is profit, although it's not that large a bankroll yet), and I definitely still enjoy it, but it's more the appreciation of a game well played, rather than the excitement of a big gamble.
PokerStars is better than somewhere like Bet365 for someone who wants to play real money poker but isn't that good yet, because they have the smallest micro stakes games around, and that's where you should start. Personally I'd recommend learning Limit games before No Limit, because a few bad calls won't be as costly, and you have to learn the value of the cards in Limit, and you can then expand that knowledge with the psychology and value of your position at a table that becomes so much more important in No Limit games. I'd also recommend starting with a very tight style of play, only playing a few very premium hands, and gradually loosening up as you get more of a feel for the game - because with the premium hands you'll have a better chance of winning and will less often be in a situation where your hand is far behind your opponents.
