Hey welcome to Steemit! I just joined myself, but I have been investing for a short while and have learned a few things.
If you are looking to make your first investment, don't try to buy anything right away. Even if the market looks good and the coin you have your eye on looks like a good buy at this time. Take at least a week of time looking up more coins and watch the market move. Get familiar with how the trading systems work.
Diversify. Even if you don't have much.
You will notice coins move up and down with the market. Read some white papers of coins you are interested in (at least skim it, but never skip it). Make a top 5 list and watch them for at least a few days. Find their support levels and make a good estimate on good entry points for each. Also, it may be helpful to find coins that have negative correlation (when one is up the other drops).
Start small and start slow. Trust me there is plenty of time to make money. Even when you are not investing in alt coins, you are still investing in Bitcoin by just holding it. Be patient and you will find your moments to make money.