1 - You are capable of buying many houses throughout Skyrim (Many of which are attached to quest lines), so eventually you'll be able to save and hold as much stuff as you want. However, as you're generally adventuring, I only keep items with at least 10 value to 1 unit of weight. For selling. Stuff like weapons, armours, and other special items should only be picked up if you can make some good coin off them. Or, if the item has an enchantment or a specialized name, then keep it until you can either sell it or store it. As I said, there's an option to buy a house pretty early on in the main quest line, so up to that point, only keep the stuff you directly plan on using or selling. Once you get a place you can store goodies, you can offload items and stuff in your house.
2 - Seriously, the only real difference in races is their special abilities. Their starting stats mean nothing. IF you wanna be a bruiser and just hit things till they die, play an orc. If you expect to spend a lot of time in the cold and want high frost resistance, chose a nord. If you swim a lot and want protection against poison, chose an argonian. Honestly, that's the only real difference in endgame. PErsonally, I always go high elf because I get extra magicka and an ability that allows it to regenerate super fast for 60 seconds, basiclly giving you unlimited magic for the duration of any one battles. I don't really have much advice in this category, but I will say you should look at whatever special abilities each race gives and go with that, because stats mean basically nothing once you've found your way.
Skyrim is a truly great game, even if its age is showing (it was pretty janky even when it came out.) There's plenty to do, you could lose yourself for hundreds of hours and still not see everything the game has to offer. The thing about true RPGs like this is that you can play it however you want. I like to be an adventurer, mostly avoiding storylines and quest lines, instead focusing on just looting dungeons and making a lot of money.
I got it all, baby!
PS4, Switch, WiiU, XBO, PC
Vita, 3DS, Android
Top 6 this generation:
Bloodborne, Sekiro: Shadows Die Twice, God of War, The Legend of Zelda: Breath of the Wild, Dark Souls III, Red Dead Redemption II