For prototyping PCBs, there are lots of options from local vendors (like in India, PCB power) which deliver very fast within a week or international portals (like OSH Park, Elecrow and PCBWay) but have a long shipment delivery time (~ a month) for economical options.

We have used PCB power in India for multiple rounds of prototyping and they gives best quality PCBs and nearly on-time delivery. They have sufficiently good online portal for instant pricing and lots of options. But for bulk order, they seems little costly while Chinese options provides cheaper per piece price but takes lot shipping cost (and customs). So, it depends on locality and prior experience with particular vendor. We have tried PCBWay for prototyping and the quality and shipping time was good for India via DHL. I will recommend to try out the vendor for a small round of batch production before bulk manufacturing.

For assembly of SMD and TH components during the prototyping phase and small batch production, we have done it by hand soldering. We were advised to use components bigger than 0805 for resisters/capacitors, but based on package availability of ICs, we have to go to very low footprint size like 3 mm x 3 mm x 0.65 mm 20 lead QFN package (8mil distance between pads (edge to edge)), but surely we should avoid using QFN packages for hand soldering.

This video by EEV blog is very useful for beginners.