I would suggest four things: become very mobile, get into Forestry bees, do some research on good material mixtures for Tinkers' Construct weapons, and become an automation nut.
Mobility:
One early-ish item would be the hang glider. If you get a running start off a cliff or a tree, you can glide for long distances rather quickly, and it makes long-distance travel quite easy. It probably cuts forest travel time down to a third or so, and that'll add up quickly if you like to explore or if you and your friends have bases that are more than ten chunks away from each other. Jetpacks are certainly nice to have as well, as they let you use the hang glider without having to climb trees anymore. The hang glider moves horizontally a lot faster than more of the jetpacks (maybe 2/3 of the tiers?), so they're primarily good for getting height and letting the hang glider take over. With armor, you'll be working your way to Draconic Evolution armor, but you'll step through a few other mods first, such as IndustrialCraft 2's nano suit and such. Even though IC2's later suits have jetpacks built in, I prefer the Simply Jetpacks for the chest slot and just use the pants, boots, and helmet from IC2. Haven't hit DE yet, but that's another big step up in mobility.
Bees:
Since you don't have chickens like in Sky Factory 3 (absolutely amazing modpack, once you're done with this one), you'll have to rely on bees if you want auto production prior to ender quarries and such. As you start exploring, you'll find bee hives all over. You'll have to make a scoop so you can collect the Forestry for Minecraft hives (not the Pam's Harvestcraft ones) and start breeding the bees you find inside. If you have trouble finding them, set your minimap to night mode. The hives glow and provide a light source, so you can look for glows on the minimap to find them as you move around. It won't seem like it at first, but drones are really the important bit. Princesses/queens are obviously necessary, but the drones are essentially your gene storage units, so always keep some spares of your best in a chest somewhere in case you mess up some breeding and need to smash several generations into a princess for a reset. I've found about 6 generations will get you back to the start if there's a princess of the wrong breed and you want to copy a different breed you have going already.
Rocky bees don't produce anything of value, but they're kinda like free-bees (lol) for feeding your other species. But you'll need to be careful with them because they default to only one new drone per generation. Multiple drones will be crucial to breeding so you can pick the best and toss the rest. So I'd start pretty early on trying to crossbreed some high-drone output bees with rocky bees to up the default drone count. Then once you've brought them up, you can keep a queen and some drones aside so the next time you find a rocky hive, you can instantly raise its princess up to par by hitting her with several generations of good drones before crossbreeding her with other bees for whatever purpose.
Down the road, they'll produce many of the precious materials you'll want, basically for free, especially once you get to the draconium bees, which lay draconium dust from Draconic Evolution. I let one of those run forever (I hit the bees hard early on), and by the time I was ready to use the dust, I had over 8,000 saved up. I'll start blazing through that soon, especially once I get my DE energy storage set up.
Make sure to progress to the alvearies as soon as you can. They take up a heck of a lot more space, but they let you greatly heighten your chances at mutations and speeding up generations. for breeding out certain traits. And those traits can be bred into other breeds by crossbreeding them and then purifying them across generations. I would recommend focusing on only one trait at a time while you're crossbreeding. If you try to track several genes at once, you'll start going in circles. Once you get good at the process, you can track two at once, but it still leaves room for messing up pretty bad. So again, make sure you keep some spare drones around, because YOU WILL MESS UP AT SOME POINT! And when crossbreeding to pull a trait over to a different species, make sure they don't mutate together. If they do, you'll probably run into problems of getting a new breed when you just wanted to make them have more babies each generation.
Once you've gotten to bronze bees, start them running and let them run and run and run and run. You'll need a ton of bronze as you move out of the alvearies and into Gendustry. I don't know what the recipes are like in regular mode, but in expert mode (I'm playing through that right now), it takes something like 33 bronze ingots for a single industrial apiary. Gendustry also offers ways to replicate genes from one bee to another, so you don't have to keep crossbreeding once you have the genes you want. You can just run a batch of bees through until you have the gene set you want, then imprint that onto any breed you want in one shot.
I would look to get your standard metals, bronze (mostly for Gendustry), diamond, coal (for turning to coal coke and powering various machines), yellorium, blutonium, cyanite (these three are for Big Reactors), and draconium dust all from bees down the line. There's more that would be useful, of course, but those are some core bees you'll want producing for you. If you're playing expert mode, you'll also need the infinity bee to get into Gendustry.
Tinkers' Construct:
There are some seriously OP combos out there, if you know how to find them. I've found general web searches to be the most helpful, and they often take me to Reddit for special weapon setups. I experimented some with the crossbow and found that pink slime is a fantastic material. I don't remember offhand what the other material was, but I think it was just two. And my crossbow does 9 damage to the wither each shot and reloads in about one second. I can one-shot some mobs with a headshot with it, which is major for swarms and creepers. My bolts are ardite cores with enderium tips, and I think slime fletching.
The bolt core construction is a bit confusing, and it's been a bit since I did it. I think you make a tool rod you want for the core, put it in a table, then pour the tip material over that to make the core and add your fletching in the heavy table (*Whoops, forge*). I put mending moss on my bolts so I don't have to worry about running out except in extreme situations. Basically unlimited ammo is quite handy.
Automation:
Learn to automate everything. Every time you get a new machine set up, start thinking about how you can set it to run itself. Once you get your base built up a fair bit and have your hands in a fair number of mods for different things, it will amaze you how much time is spent just putting fertilizer in this or restocking the coal in that. Linking machines together so they feed each other is great, as is having input-output chests on most of your setups. Dropping off an inventory full of wood for making into charcoal, then having that furnace setup feed into itself and 3-4 other machines nearby will free up your time immensely for other projects, like crafting the next tier of jetpacks for getting around faster or going and finding AE2 meteors for their treasures.
Thermal Dynamics are a great mod for pipes. Extra Utilities' transfer pipes are also pretty decent and allow for nesting (cascading inside of each other) filters to cover big groups of items, but they're a bit more finicky if you're routing pipes next to each other in tight spaces. Ender IO conduits are fantastic pipes, but it's usually a later-game mod.
Applied Energistics 2 is a later-game mod that will tie into automation big-time. It has machines that can automate creation in various ways, and it can interact with machines from any other mod in the pack. At its core, it's a computer-storage mod so you can get rid of all those ugly chests, but it also allows for exporting your items into machines automatically if you run out of something (like throwing some stored logs into a furnace if you need charcoal, then returning the charcoal to storage so you can just send the request and grab it out a few moments later).
Project Red gives you a lot more compact and flexible redstone items like single-block timers, redstone cables that run up the wall, etc. Those can make for much more efficient automated machines and such. I've used just the timer in several modpacks even when I didn't touch anything else in that mod.
I hope that helps!