This guide is not complete and will forever be a work in progess as I see fit. If I do find to enjoy making this type of stuff I will be updating this as much as possible.

LANE MARKING
You always want to mark the ADC if you are playing vs an engage or tankier support unless they have an ezreal, if they have ezreal mark their support. Playing Enchanter or Poke supps idealy you would like to mark the support, ever since the starter item buffs, the supports have become a lot squisher and easier to kill especially at lvl 2 and lvl 3 spike.
Very rarely will you go for jungle camps as they are super hard to take for laners now and are usually just a tempo killer. The only times I would recommend going for scuttle mark is if you slow pushed and crashed 2-3 waves into enemy tower and you have 30 ish second for free, other situation is if you can hit the mark to get it low and then have your jungler take it so you can be running back to lane whilst getting your mark from scuttle. IF YOU EVER GET BOTH MARKS ON ADC AND SUPP, MARK EITHER JUNGLER OR MIDLANER DEPENDING ON WHICH ONE YOU THINK WILL TRY AND GANK YOU.

MID GAME MARKS
Mid game marks are arguably the most important because of how hard you can snowball. Normally you would like to keep mark on ADC if you can keep getting it consistantly but I like to think of who would be engaging the fights in mid game. Mid game fights are usually initiated by Melee Supports, Tank tops, or Skirmishing Junglers. Your main goal in mid game is to always have the push in mid lane so you can roam to these fights first and have numbers advantage, that shouldn't be hard unless you only have 1 or less mark.

LATE GAME MARKS
During late game there should be a lot of towers gone on the enemies side so it makes it a lot easier for you and your team to invade together to get these marks and take camps from enemy jungler, also marks on Dragon or Baron need to be prioritized as they are important objectives as is.

Laning
If you are playing Kindred for the first time, you wanna treat it like Lucian and Vayne hybrid. You want to go for lvl 2 if you are allowed to hit the wave because you will pretty much always win at lvl 2 spike if they fight you in your W. Your main harass will be Q Auto and then run away with fleet proc. Your champ spikes at lvl 2 and lvl 3, and you should always be looking to fight at these spikes. Kindred is also a very strong skirmisher once she hits lvl 6 and around this time you should be trying to get your jungler to fight dragons with you.