All you need to do is turn up, I can guarantee that you'll make friends fast at any airsoft site, since you share an interest with those who are there. People are almost universally friendly in my experience, and despite the fact that Joe Public might imagine we're all nutters, generally speaking, everyone I've ever met at an airsoft site could not have been more pleasant if they had tried. Almost everyone will welcome a new player as long as you are interested and play fairly and safely, so pay attention at the safety briefing, and if in doubt, take the hit. Everyone likes showing off their gear, so opening a conversation in the safe area or at the briefing is easy to do: 'Wow, that's a cool gun/mask/pair of boots...' etc.
Just go for it, you'll fit right in before you know it. Call up your nearest airsoft site and ask about hire packages, then just make sure you've got some decent boots or tough trainers, and wear clothing which will allow you to feel hits, but not have them hurt too much, i.e. cover your neck up with a scarf, wear a long sleeved top and some thin gloves, and maybe a baseball cap or something similar, the site will provide a mask to protect your face and it will probably only cost you about 20 quid or so for an evening session with one of their hire guns. I would recommend going to a few skirmishes and using their hired weapons rather than buying something straight away, the experience of a few fights and seeing what others are using will allow you to determine what weapon(s) to buy if you want to get more into it, which you almost certainly will, because it is great fun.
