Another one of the key basics you will need when learning to reupholster... WEBBING! This is the base on which your springs will sit on in traditional work and your foam in modern. Its really important that you get them nicely secured as you don't want your bottom dropping out ;P
For securing webs we usually use 12mm or 14mm tacks (these are on the larger side, I would usually use 10mm for most other things) as you really want to make sure your webs are secure in the frame. For traditional chairs you would usually use jute webbing, for seats you often use black and white webbing as its better quality and maybe the brown in the arms. You will often use elastic webs in modern work. Begin by folding over the top edge and putting in a W formation, don't go too close to the edge or you will feel your webbing threw the top fabric.
WEB STRETCHER, another really useful bit of kit, allows you to stretch the webbing much tighter than you would be able to by hand.
Add your tacks on to the other side, again go for the middle, remember you want the edge nice and smooth,
Fold back up and tack, again you will be making the W shape or M this way up, this ensures the webbing is evenly distributed.
Continue webbing its best to start in the centre and move out, when your doing a bigger frame you may want to lay it out first so that you can work out how much you need to spread out. You never want more that a web width gap, in some cases that you will be putting springs on top of these so the last thing you want is them being able to slip out.