Absolute beginner - want to start in shares

Hi all,
As stated above I am looking at investing with shares. This is something I've been interested in for a few months.
I've done a subsequent amount of reading on the topic and decided to start doing some dry runs on ASX.
I have an account with CommSec to help me out a bit and I thought their brokerage percentage was reasonable.

I just have a few questions before getting started:

What is an ideal amount to start investing in shares? I have been told $2500 should get you going.
Please keep in mind my expectations of investing is to gain capital growth, but to start with, in small amounts.

What is the best way to know if to invest in a company? Is it best to follow their stats over x amount of time, and go off of a pattern?

What kind of research about companies is crucial? I am aware that ensuring the growth of the company is rising, but in terms of making judgment wether it will decrease?

If mistakes are made and money is lost, what key things do you take from that? How do you know what to learn from?


These are all i have for now, but no doubt will have more. Please bare in mind I have never made a trade before, I am seriously interested in conducting trades, I am only 20 years old and have a decent amount of money to invest with.

You need to find out what you're comfortable with 'risk comfort zone' also with Commsec's $20 brokerage thats 0.8% on a $2500 trade, 0.4% on a 5K trade, make watchlists and add stocks that you think are cheap, come back a day, week, month later and find out if your right.

I think that for a beginner, a good start will be opening a demo account with one of the broker firms and try it out for couple of weeks. After this period you can go and trade on real money when you feel comfortable enough.