HELP! Why wont this work?

I am new to trading and have never traded on a real money account. I am currently testing a strategy on gold futures trading. I am using the ThinkorSwim trading platform with REAL time data and quotes(so they say).

In my strategy is scalping strategy I suppose. I look at the 1 minute gold chart and determine support and resistance levels, when the price hit one or the other I go short or long. I set my limit order 2 or three ticks above my enter price, which will give me a profit of $20 or $30 per trade. Commissions and exchange fees cost my $3.76 per contract, so $7.56 to enter and exit a trade. I set my stop loss order at 10 ticks. I 2 tick profit can give me $12.48 profit per trade per contract. And If I can make numerous trades per hour I can have a decent day.

I am looking for reasons as to why this wont work. One reason I can see is that the bids and asks are easy to get into on the live simulated trading whereas on a real account it may be a little tougher to get into a trade at the desired price.
I ask myself "If it's such a good idea, why isnt everyone doing it?"
I try to justify this by saying that not many people are going to settle for making $12.50 per trade but and most people don't care to sit and look at a chart all day.
Any help will be greatly appreciated!!

Resistance and support levels are interchangeable, that is, once a support level breaks it will become resistance. You never know if there will be any resistance levels in a bad day, there are actually few people who can manage emotions perfectly when seeing huge price drops. Google herd theory, it may show you a clearer picture.
In theory, you will make as much as you desired if everything goes smoothly. However in reality, the amount of money you can make depend largely on other people, especially those big players, because your resistance and support levels cannot be exactly the same to what they think. As a result, when you buy at support, others may continue dumping their holdings, it's impossible to make money in this situation. That's why your theory won't work.