Equipped gems level up as you make XP, receiving ten percent of poe currency of the foundation XP granted from monster kills. So you can quickly level gems by replaying areas which are a few levels lower than your existing level.
Every part of loot you acquire takes up varying levels of room in your bag. To take as many potential things at the same time, you have to move items around and squeeze things into the allotted spaces. Even then, your luggage is likely to fill up quickly if you pick up every single item you encounter.
The trick, then, would be to discount items that your character can not use or are of reduced price.
You can pretty much ignore white items unless you're about to go back to town and have the space to spare for them. Rarer items are often worth picking up and promoting, even in the event that you need to hold onto them for a short time. And of course, any product that looks better than your existing gear is well worth catching -- even in the event that you need to lose something else temporarily as you equip it.
By default, figures do not regenerate life but they do regenerate a very small amount of mana every second. You are able to manually refill life and mana using the appropriate kind of flask. Flask charges automatically refill when seeing a city or hideout. They also gain charges from killing enemies. Equipping better flasks increases the quantity of daily life or mana regained, and can have other effects too.
Still, you will have a hard time if you only rely on flasks for life and mana. Gear and passive skills can boost regeneration for stat or even steal life and mana from hits and kills. Taking into consideration the life and mana restoring properties of gear is important to maintaining your health and mana pool up. At bare minimum, you want to have some life regeneration so you can recover health between battles.
One more tip to think about: if you're fighting with the POE match solo to buy poe orbs, you may generally invite a friend or Path of Exile participant from city to assist. Don't take your exile sitting down!