Trading strategies vary greatly from person to person.
You can hold a position for seconds or for years and the system you use for getting into or out of a position can have almost infinite variations.
Think of what you did when you were trading on the simulators. Did you have a particular set up you looked for when you decided to get into a trade, why did you exit the positions. Which trades worked and why do you think the losers didn't. How long did you hold the stock for?
If you think about these it may help you when trying to focus on a particular strategy / style yourself. There are lots of different ways of making (or loosing) money. You need to find a way that suits you and your personality, tolerance to risk and what you are most profitable at.
If you are good at poker then you probably already know how to do this with your poker game, just use the same analytical skill on trading now.
As far as spread betting is concerned, I too agree that it can be a great way to start. It has it's problems, but it also has it's advantages such as only needing small amounts of money to start and having a 10:1 leverage on your account.
The shorter holding periods don't work well with spread betting though, as you have to cover the spread before making a profit, and when you exit at a loss when the trade isn't going your way, the spread also adds to your cost.
In my opinion, holding over 2 or more days is more suited to spread betting than opening and closing positions in the same day (intra day or day trading as it is known).