The single most important thing a new character can do is find a mentor.
I mean "mentor" broadly: a more experienced character who can show you the ropes and help you out. This is doubly or triply important for a player who is new to the game. A person playing their first or second character should ABSOLUTELY NOT try to go it alone by playing a disagreeable loner or someone with difficulty forming attachments to others.
A mentor doesn't need to be a samurai sensei. In fact, my experience is that single most common "mentor" character is a lover. HELP CHASTITY aside, that IC trade off tends to be easy to understand and that's a person with an investment in your character's happiness. Almost as common are bosses, friends, or any of the PCs who act as shadowy "patrons" of some ideological cause or another.
Mentor characters help blunt a lot of the difficulty of being a new character or a new player. They provide access to a network of friends, usually have flash to replace trivial losses like a dipped phone, can connect people to plots and factions and usually either are strong enough or have friends who are strong enough to deter some of the predatory violence which targets characters in the "two weeks to two months" zone where they have enough flash and gear to rob but not enough skill or smarts to protect it.
Most of all, mentors -- whether they are teachers, lovers, co-workers or gang associates -- are a resource to answer the frustrating "how do I do this" questions ICly. A lot of things in Sindome are IC secrets that aren't terribly secret; people won't answer the questions on pubSIC but will happily answer it in bed or over a beer. Having a mentor you trust is how to get over that curve, and even if they betray you that ends up being great RP.
The TLDR is this: do not try to go it alone. You, the player, are the arbiter of your character's choices. Make choices that cause your character to become connected to someone more experienced and then lean on them for the first few weeks and months until you can stand on your own and do the same to someone else who has just come through the gate. Not only does that create a lot more RP it builds the social networks that drive the politics and economy of the game.