Haha, well.. First, assess what type of lane you're in, in terms of threat to your p1. For example, if you are lich babysitting a PA vs a high-damage/high-nuke offlane, especially one with disable, you'll want to prioritize zoning the p3 *or* the p4, and securing ranged, as well as giving your PA cover (someone to jump to). I typically don't pull at 1m, but if your carry is secure you can use this time to deward your small camp and/or maybe get a half pull off (where you only grab the ranged and 1 melee; the purpose of this is that if you only have 1 iteration of your small camp, especially if it's little shitty creeps, at least 2 of your wave creeps will get denied). You can essentially eyeball the pull, as the time will vary slightly for different creep types and different heroes (e.g. if I'm ogre magi and the small camp are those slowing ghost bitches, I want to pull a little bit earlier than I would if I'm, say, lich, and it's kobolds or something like that).

TLDR - Learning matchups to be able to quickly ascertain how much threat your carry is under will let you know how much leeway you have to do things like deward your pull camp, pull creeps, obtain the 3+ minute runes, etc. If you're playing a high nuke p5, you can spam mangoes and zone, to give your p1 room to breathe, as well as nuke the ranged if p1 can;t hit it. If you're playing a more babysittery p5, try and back off as much as possible to let p1 soak xp (especially if they benefit heavily from their 6, such as a Slark, because once he gets it he's much safer in lane), but don't go too far. Pulling should only be done if your p1 is relatively safe for 30 or so seconds without you.

I'm sorry, I know it's a lot of information. ><