Materials are a lot more important than food. One above poster said it would be OK to go with just 3 food, but I would go even farther and say that it is OK to go with even 2 food.
Having 4 materials is a lot better than 3. It means you can build things 4/3 = 133% of regular speed right from turn 1. Further, that means you can build buildings that increase your production faster (Lumber Mill, etc). Bringing those online faster brings everything else online faster.
It is a snowball effect.
I will take a good 2/4/2, 2/5/2, or 2/4/3 tile starting out over a 6/3 any day. Having higher level cities is nice, but if you die before you ever get there then it doesn't really matter. Also take note of the natural resources nearby to where you start. Start your city next to a forest or river tile if at all possible, forest especially. They give you early buildings that boost production (see Lumber Mill).
As far as what you should try with your sovereign to get an early game advantage, I find Binding to be very powerful. It gives lots of free units starting from really early in the game. If you go this route, research the magic tech early that lets you make the more powerful shard shrines and you can get the mid tier units starting only a few turns into the game. If they die they just respawn again too a lot of the time. At the very least you can use them as city defenders and make your cities really hard to defeat.
Binding is great, because elemental shards are very abundant in the game. One shrine will give you a "young" elemental right away and then a "normal" elemental when you upgrade the shrine to the next level. That is 2 separate units per shrine early game. It can make a third "ancient" level elemental, but that won't be for a really long time. Luckily, the units you do get pretty much ensure that you indeed survive a long time. Those units are pretty tough too when they do come out, and completely free again.
Make sure you take some kind of magic with your sovereign too, because if you are getting the most out of Binding you will have a lot of mana available to use spells with. I like Air, Earth, and Death the most (in no particular order).
- edit - typo