1. Getting steel production going is a must, as is creosote oil; but don't go dumping iron into your blast furnace, as you won't need a massive amount, likewise don't make too much creosote oil, as you won't be needing a lot of it unless you go heavy into Immersive Engineering.
2. Peridot, sapphire, and ruby are plentiful, and have decent stats, as such they make great early Tinker's Construct weapons and tools.
3. The water wheel from IE is great for early power due to it not needing fuel, but you should make an HV capacitor stack as a buffer for when you will be using the assembler.
4. When you chain IE capacitors together, only draw from the last one in the line, since if the last one is charging or draining faster than it is refilled, you won't be able to draw from any in the chain but the last one.
5. Get the tool forge as soon as you can, to make a hammer, which will greatly improve your material gathering; I suggest making the hammer from steel, and that you get a /dev/null and set it to cobblestone.
6. For emeralds, go into the mining dimension and find a highlands biome, mine between the y-levels of 16 and 20.
I will update this progressively as I remember or think of more, and welcome any tips in the comments.