I'm at a roadblock.

[Overene]

So, I'm at the part of the game where I always get stuck, which is with blue science packs. I have no idea how I'm supposed to effectively mass produce them, and I always end up having to just make them manually when I need them, which is about as boring as you could expect. I can create all of the things needed to make blue science packs, but all those things are produced at different rates, and the entire system falls apart when I start running out of resources

[roy7]

Well a couple choices. If you make all the resources, just expand whichever one you end up short of. If it's more of an issue in getting everything organized in a reasonable way, sometimes I'll hand-craft enough packs to get logistics network up and running, then let robots do all the heavy work.

[Koub]

I personnally use viewtopic.php?f=134&t=5576 to get an idea of the ratios I need at every stage of a production. I add an output node for the end product I want, with the rate I want it out (like 30/minute), and add an infinite input node for everything I have on my main bus.

The next step is to ensure you have :
- Enough raw material on the input
- Enough throughput on your main bus to feed the beast
- If you have intermediate products on your main bus, chech you produce enough of them.

[Serenity]

Science pack 3 is supposed to be challenging because you need to get an oil industry up and running for red circuits and sulfuric acid. But you don't need to get the ratios absolutely right. That's more for the case when you want to constantly research, which isn't really needed. If you do that you will have technologies researched way before you can really use them and will just burn through resources. Currently I have 3 Red, 3 Green and 3 Blue, which seems to work fine, but is not the recommended ratio. At least with a long belt of blue science, so I have some buffer. That way I have quite a bit of beakers lying around when I want to research something. Probably wouldn't work as well without using the belt as buffer. Leave room so you can expand it as needed.

There are way better setups, than this, but it just shows that you don't need the best and prettiest:

[Xterminator]

Yeah blue science is certainly a challenge. I struggled with it a lot the first few times I tried to get it all working.
At this point I find it easiest to just go through it step by step.

So first I figure out how many blue packs I want to produce. Typically it is 12 assemblers worth since the packs take 12 seconds then I'm producing essentially 1 per second. Then we look at how many materials each pack takes. Off the top of my head I believe it is 1 of each item in the recipe. So at this point we know we need about 1 of each of those items made per second to keep up.

At that point it is just really going about setting up the production for each item. Keeping in mind we need 1 per second then we can just look at the time it takes to produce one item and figure out how many assemblers/chemical plants are needed based off that. For example, smart Inserters only take half a second, so you will be fine with only 1 assembler making those as long as you can keep the needed materials flowing in for it constantly work.
Advanced Circuits take 8 seconds I believe, so you would need 8 of those to get 1 made per second. So on and so forth with the other items. Then the real trick is just keeping all those products fed with the needed materials to run them all the time. :p

That's part of the fun and challenge though, right?
Anyway, hope this helped a bit.