Yup, this looks like a good basic guide to character building. At least, I know I pretty much do all the above when making characters.
With regards to this, though
1. Specialize
If improving something you're good at costs the same amount as improving something you're bad at, improve the thing you're good at. Since you're good at it, you'll probably try to do it a lot. That'll give you more chances to use that improvement. For example, if you have a +1 spirit control specialization, a Refinement giving you +1 spirit power and control is better than one giving you +1 spirit and fire power. You'll cast more spirit spells than fire spells, so you'll use the spirit bonus more.
I'd add a caveat that if the thing you're bad at is important (Like a primary social attack roll in a game you just realised is heavily political) or critical (like defense rolls against attacks), then it might be worth it after all. It's all about value for Refresh
Also
3. Have a plan
Make sure your powers fit together properly. Don't take Inhuman Strength and Channelling (Fire). Have a goal in mind, and build towards it. This is easy for some Templates like the Wizard, which have a good plan built in. It's not so easy for some Templates like the White Court Vampire, which inherently pull in multiple directions at once.
If you have a character concept that requires disjointed powers, it might be worth working something out with your GM to tie it into a unified set of rolls. In my games, for example, I allow wizards with Inhuman Strength to gain the benefits of it in their magic - so they inflict 2 additional stress when attacking targets with physical spells and gain a +1 to control rolls for such spells, and gain +4 complexity to spells aimed at moving heavy things or similar Might-replacement rituals. Fluff wise, the same force that empowers their physical bodies also empowers their magic (think Harry Dresden becoming stronger and more magically powerful after becoming the Winter Knight)
Also, I know this is a matter of opinion, but a general rule of thumb I use to determine if a power/stunt is good is to equate 1 Refresh worth of power/stunts to 1 free Fate Point every session. If it's at least equivalent in value, then it's a good buy. For example, a stunt giving a +1 to your primary attack roll will be used at least 3-4 times in a combat scene, so it's equivalent, all in all, to maybe a +4 bonus, or 2 fate points. Assuming combats occur somewhat frequently, then its value is as good as a free Fate Point per scene, so it's a good choice.