The Fighter and Mage starts are both pretty strong with good stats. There are only 5 levels total planned for the character in this game, most of your stats and combat abilities will come from gear, skills and quest rewards/achievements. Only a little bit will come from the actual level becaue your level in this game symbolises your Rank within the army rather than a typical level seen in most RPGS.
It already exists, go into your items and find one called "Sprint Toggle" you can then use that to set yourself to always sprint. You can also bind it to a Hotkey to toggle the sprint On and OFF any time once it's bound.
If you mean you want to raise your construction Skill to level 2, you need the Construction Bench and to craft items in it until the bar on the top right side fills up, then you will level it up to level 2 automatically. This is a long process!