Once you've got a stable food supply and some basic armor (following the survival guide), it's time to move on. Staying at spawn forever won't get you anywhere, so if you want to "rank up" in the server by getting late game armor, then you have to move out.
Step 1 - PreparationEdit
Before you go out into the wilderness, it is good to prepare.
First, use hacks! You will need to X-Ray out any potential bases, track potential enemies, and find fast escape routes. If you don't, you're at a massive disadvantage!
Have at least 1 stack of food source, as you will be moving away from your farm and getting food along the way is annoying.
Have at least iron armor, to protect against mob attacks.
Have an arsenal of tools ready, including a bow, to protect yourself.
Have a stack of wood, because you'll need to build out if you fall down.
Step 2 - Overworld WalkEdit
If you are not that far from spawn (<10K) and you are in the overworld, it is not recommended to jump into a nether portal right away, as spawn is choked with withers. Instead, it is recommended to go at least 30K away just to be extremely safe. Also remember to create your own nether portal, as there is a chance that it could be a "trap" portal.
Step 3 - Nether Walk Edit
Once you've got the obsidian, you need to go through the nether to walk faster. Make sure to carry enough obsidian and flint and steel to make a return trip!
Also get a bunch of stone picks and some diamond ones as well, as you'll mainly be going through the ceiling to avoid mobs.
You can avoid (most) tunneling by going through the middle (Y=40-60), but obviously it is more risky.
When you arrive in the nether, make sure no one is following you, and start tunneling. If you want to drive off followers it is recommended to tunnel a bit, walk several hundred blocks normally, and then tunnel again. Also try to set up a bunch of intermediate portals to drive off anyone who follows through.
Because of the way nether portals generate, you most likely will be placed near someone else's tunnel. If you are thousands of blocks off both axises, you will not encounter other players, as they will usually be traveling on an axis.
Once you've gotten to your approximate destination, you can built a portal and go back.
Step 4 - Overworld Walk II Edit
After you've entered the overworld again, remember that is NOT where you base. You've got to go away from it so anyone who potentially finds your portal can't find your base.
Also, for 2b2t, don't base next to a village or generated structure. People are obviously looking for these structures for loot, and you don't want them to find your base next to it.
Step 5 - Basing Edit
Place your items down in a chest, and start mining resources for your base! It is practically useless to try to "conceal" your base by hiding it in a tree biome or by using natural resources, because if someone goes near it with ESP they're going to find it no matter what. The best way to hide the base is to make sure no one goes near it in the first place.
Make sure you know where the villages are, because trading will come useful once you can farm for resources!
What I would do is create crop farms, mob grinders, and eventually resource grinders. These help you quickly mass the resources that villagers trade, which will unlock lots of other resources.
If you are going to put down a bed (which is recommended) it is best to put dozens of beds, so in the case that someone does find your base and they want to trap you, you'll be able to get out.
AFK-Fishing also works really well, because you're far now, and no one will be able to disrupt you.