Staying on cam longer does not necessarily mean more money. The only way staying on longer would benefit you is if you know you are going to make at least $X per hour, or if you need to build up to an earning hour (for example, if your shift is 3 hours, you may make only a little money during the first two hours, and then when everything is set up, you may make big bucks the third hour).
For most women, they do not begin earning immediately after logging in. It can be a pitfall to log off after 10 or 15 minutes when your room doesn't immediately fill up with members and tipping starts. I would give every session on cam at least 30 minutes (or an hour) to see if things start to warm up. Otherwise, I would leave.
If you have been online for a full hour or two and things aren't getting busy, they aren't very likely to pick up more just because you stay on cam longer. If you are satisfied with your hourly earnings but you're just bored, put the TV on in the background and hack it out :lol: if you're bored because you're not earning, log off and try again later.