You can make a start to learn how to make better investing decisions by learning and understanding what your current super funds are invested in. Does the super fund give you choices of where you can invest your funds, and how often does it allow you to change your investment choices each year?
If you are interested in one area of investing over others, eg property or shares, then you should learn more on this subject, as you can also start investing outside of superannuation. Your funds in superannuation are taxed less but you are unable to touch them for another 30 to 35 years. You also need to consider investing outside super to help meet your more medium term goals and grow your wealth outside of super as well.
If you are interested in shares then I believe you should learn about both fundamental and technical analysis, they can help you to make wiser decisions about what to invest in and when to invest.
Above is a chart of the ASX200 over the last 20 years until January 2015. It shows the Rate Of Change (ROC) indicator below the chart. This can be used to make medium to long term decisions in the stock market by investing when the ROC is above zero and getting out of the market when the ROC is below zero.
Regarding your aggressiveness in your investments, most would say that yes because you are still young you should be aggressive because you have time on your side, so if there is a downturn in your investments then you still have plenty of time for them to recover.
I have a different view, and I will use the stock market as an example. Refer back to the chart above, I would be more aggressive when the ROC is above zero and less aggressive when the ROC is below zero.
How can you relate this to your super fund? If it does provide you to change your investment choices, then I would be invested in more aggressive investments like shares when the ROC crosses above zero, and then when the ROC moves below zero take a less aggressive approach by moving your investments in the super fund to a more balanced or capital guaranteed strategy where less of your funds are invested in shares and more are invested in bonds and cash.
You can also have a similar approach with property. Learn about the property cycles (remember super funds usually invest in commercial and industrial property rather than houses, so you would need to learn about the commercial and industrial property cycles which would be different to the residential property cycle).
Regarding your question about SMSFs, if you can increase your knowledge and skills in investing, then yes switching to a SMSF will give you more control and possibly better returns. However, I would avoid switching your funds to a SMSF right now. Two reasons, firstly you would want to increase your knowledge as mentioned above, and secondly you would want to have at least $300,000 in funds before switching to a SMSF or else the setup and compliance costs would be too high as a percentage of your funds at the moment ($70,000).
You do have time on your side, so whilst you are increasing your funds you can use that time to educate yourself in your areas of interest. And remember a SMSF is not only an investment vehicle whilst you are building your funds during your working life, but it is also an investment vehicle when you are retired and it becomes totally tax free during this phase, where any investment returns are tax free and any income you take out is also tax free.