How to meet other actors

There are numerous ways to meet new actors and when you do it is important not only exchange contact details but to make an effort to keep in touch!
The easiest way to meet fellow actors would be on an acting course taken at university or college, or even at workshops or an evening class, in these environments all students are in a similar situation and usually experiencing the same obstacles eg - finding an agent or getting their first TV credit. You will find that usually two heads are better than one, advantages would be you can attend networking events together (confidence boost)and provide each other with moral support on those days where you feel stuck in a rut.
Another way of meeting actors would be networking events specially for actors or even film/casting directors (as many actors attend these also), so first you would need to research where the events are going to be held and what format the event/semainer will take and then once there be open and friendly and I find it useful to distribute your business card (with your headshot imprinted) this way each person you meet is sure to remember you.

The most common way in the social media world we live in today would be through actors forums easily found on various casting sites, this way you can start a conversation with actors in the same predicament or who would like to see the same theatreshow's as you for example.

Last but not least you could always advertise yourself on a website by setting up an actors theatre group, for example offering to meet with a selection of like minded actors to put together your own production or show, this way the actors contacting you are more possible from the outset as its a mutually beneficial process of you all having a stage to promote your talents.