To enable Network Intrusion Detection System (NIDS) mode so that you don't record every single packet sent down the wire, try this:
./snort -dev -l ./log -h 192.168.1.0/24 -c snort.conf
where snort.conf is the name of your snort configuration file. This will
apply the rules configured in the snort.conf file to each packet to decide
if an action based upon the rule type in the file should be taken. If you don't
specify an output directory for the program, it will default to
/var/log/snort.
One thing to note about the last command line is that if Snort is going to be used in a long term way as an IDS, the -v switch should be left off the command line for the sake of speed. The screen is a slow place to write data to, and packets can be dropped while writing to the display.
It's also not necessary to record the data link headers for most applications, so you can usually omit the -e switch, too.
./snort -d -h 192.168.1.0/24 -l ./log -c snort.conf
This will configure Snort to run in its most basic NIDS form, logging packets that trigger rules specified in the snort.conf in plain ASCII to disk using a hierarchical directory structure (just like packet logger mode).