"Start at the minimum load and work up..."
The problem with this frequently quoted phrase is the degree of variation between companies' data and practices on defining 'minimum'. For instance, Norma's No.2 manual sees only 1.6 to 2.3gn reductions from max for the three powders quoted for the 150gn Nosler BST in 308 Win - a mere 4% reduction for one. Hornady regularly has its lowest listed loads at well over 15% below max, sometimes over 20%.
Back in the days when Hodgdon powders came in cardboard cylinders, the company only gave max charge weights and advised using a 6% reduction for starting loads (bar H110 which saw that figure reduced to 2%). IMO, that's about right - certainly 10% tops. Hodgdon changed its practices though, no doubt because it didn't fit the treat-everyone-as-an-idiot requirement of modern health & safety practice and US citizens' propensities to sue suppliers should anything go wrong.
On weight increments, Sierra advised 1% of the max listed weight many years ago, which seems about right so 0.5gn for 308, 6.5X55, 7X57 etc. I use a version of what
@Craigsaun suggests, especially on breaking ground with new to me powders and/or cartridges. That is, start fairly low with relatively large initial increments to get a feel for MVs, pressures, clean burning etc, then the increment size drops as maximum is approached to 0.3 or 0.4gn for 308 size cartridges / 0.2gn increments for the last few on 223 size designs. Using the lowest listed charge in some manuals for even three round batches as per Hornady will see barrels shot out
)) by the time a decent load is finally achieved. I joke, but the reductions are way over the top if you pardon the mixed metaphor.
. I may add , I am no expert and someone may come along shortly and correct me 
