as hecarim you will get so many invedase in early ( depend what rank you are ) cause your lvl 3 is not powerfull, you will lose most 1v1 against conq and lethal tempo junglers.if you get invade its better to drop the camp and not contest.

most hecarim players dont know about Q stacks.is always good to fight when you have 3 stacks on Q

Hecarim is a full clear jg,try to farm and get ahead with cS.everytime look if enemy has low Hp you can go and take the kill or if is pushing to your tower gank that lane,if you dont have any oportunity to gank just farm.also you can look for early Lv3 ganks if for example you have a laner that gets bullied a lot example katarina Vs Vex, even if you cant kill vex is a good gank cuz you help your midlaner to have a change to beat vex.

98% of your games path botlane,but if you have nautilius and samira or something with CC you can path top and gank bot after

with Hecarim is so easy to make voidgrubs,if the enemy jungler do voidgrubs and no one is helping you go to drake,mid game is the powerfull moment for hecarim if you got 2-3 kills in ealry you can go crazy in mid game.but dont risk to much, you can throw your game.

try to stay with your team and help them.you can engage with your R to fear enemys.but you can also save your teammates with your R with that fear.