First off, I play with the excellent FCR3 mod which fundamentally changes the Witcher 3 experience (for the better). This build will work differently in the non-FCR3 game. This build starts off combat with a bit of magic and then brings in alchemy later to augment, well, everything. This build avoids the alt-quen shield and whirl for more directed, toe-to-toe action.
First ~15 levels - Combat skill fast attack (first two in column), arrow deflection (lvl 1), fleet footed, and resolve. Exploding shield and delusion in the signs skill. In the general skill, the only must is whatever armor type you want to use mostly, although focus, and rage management are noteworthy. You'll want to have at least level 2 delusion by level 6 (when you'll probably start using it in conversations).
Levels ~15-30 - Keep rasing the above skills and add magic trap (very useful in many instances) and maybe start to delve into alchemy. Acquired tolerance, poisoned blades and protective coating are great, as is heightened tolerance. But your real goal in the alchemy field is synergy. It's totally worth wasting points just to get to it.
Levels 30-45+ - Keep raising the above plus crippling strike, razor focus, and undying to round out your combat skills. Once you get to the Blood and Wine DLC you can add up to 4 more slots for skills. I usually run with Euphoria so all those alchemy skills populate the center, extra skill slots and I have 3 greater red and 1 greater blue mutagen to enhance my attack and sign usage.
I didn't list many in the general skills but several are useful. In addition to the ones I listed above, I've found strong back and metabolic control useful. If you don't use the FCR3 mod gourmet is supposed to be excellent. Also, it's usually better to not spread your points around to skills you can't even equip yet because you haven't unlocked enough slots. Until I get to around the mid 30s level I have all skills slotted that I have put points into except for maybe one general skill. So when you spend a point on a skill put the next couple points in the same skill and don't buy into a new skill until you can slot it.