could you upload some First person footage on your twitch or youtube channel from a competitive game rantology? I spectated you during pub one or two times, but that isn't really the same :D
Rines gameplay would be great too ;-)
There's really no easy way to learn. You just have to pay very close attention to this and focus on learning it. For me anyway I tend to pay attention to how much dodging I have to do, the more dodging you're forced to do, the less aggressive you can be and it can sharply cut your uptime down.
But really, the only way to really become comfortable with it is practice. Learning to use metab constantly and at the correct times is sort of the same way- you just have to practice on being efficient with it... also, if you don't have metab, you're severely limited in terms of this of course, metab and non metab are different playstyles- you must play more passively if you are missing metab.
Single rifle marine:
Marine has bullets left in his rifle? -> Don't swoop in for bites; stay back and spike or do evasive manuvres to make him hit the walls instead of you.
Marine running out of bullets? -> Swoop in, nomnomnom. Dinner time.
Single shotgun marine:
Never swoop in on a shotgun without carapace, a full hit will make you REALLY low(down to like 20hp as far as i remember) from full hp. It is really a bad idea no matter what. Practicly any chip damage combined with a full shotgun hit is a death.
With carapace you can more easily survive a full hit from a shotgun, if he isn't allowed to shoot any more than that one hit, but it is still very risky. Only do it if you have backup from other aliens and you are certain to kill him before he can fire a second time or when trying to save a higher lifeform from death. Shotguns kill you faster than you kill them, you are a support class; play like it.
Groups of marines:
Never swoop in, even spiking can be risky against a group of rifles; make sure you have very closeby cover and use it. Play support, use buddy system.
No fancy MSpaint graph though and doesn't really relate to your HP. So here that comes: If you don't have armor or have very low armor, fly back to gorge/hive/crag in that priority if same distance and heal up.
Energy management is definitely one of the harder things to learn in my experience. As rant said, the more practice you have the better you'll become. To me, a lot of it has become second nature or an internal clock, kind of like knowing when you need to reload without looking at your ammo. If your spending a lot of energy dodging you'll have to be more careful about landing all your swipes when you go in for the kill. In that case, if you miss a swipe or two you might want to bail out before finishing them so your not walker fading or out of energy to blink away. Say your in an engagement against 3 marines - by the time you and your team have cleared the first two marines your going to have low energy, so you may want to find some way to disengage momentarily so you can metabolize or regenerate before finishing off that last marine.
Once metabolize is up there's really no excuse to not have 80-100% energy when engaging, so learn how long it will take you to win a fight under those circumstances. If you start going over that time and you haven't landed at least 3 swipes, you know it's time to bail, even if your not that hurt. Not worth losing your fade.