Hey Czek, I just got into airsoft in September and I love it. Here are a few little things that I kind of picked up along my learning path.
1. Do NOT buy the first gun you like! It may be expensive. These fourms are a great way to find great guns at lower prices! I have already picked up a few off the guys here for prices well below any other price you will find!
2. New is not always better! Sure its nice to have a brand new gun but its going to cost more. Look into getting a lightly used, well maintained gun, it will perform the same just cost a few hundred less.
3. PLAN A BUDGET. I though i had this one set, the plan was to spend $800 to get a gun a few accessories and some gear, since that budget was set i have near doubled it >.< Make a budget and stick to it.
4. Ask questions! everyone I have met both in games and at stores have been amazing about fielding my questions and giving me tips and pointers. If there is every anything you don't understand, dont hmmm and hawww about it ask, someone will usually be more than willing to help you out!
I hope these points help you out. and lastly BRING WATER TO GAMES. staying hydrated is important! I think it has kinda been lapsed as a must do for games, sometimes a snack is a good idea as well.
Cheers I hope all goes well