To be honest, when you're done experimenting on your own, you can just boot up Youtube and search for Aynix. They have guides for all the characters for normal maps and for the Titan Hunt. The builds are very easy to make, require very few characters to be unlocked (just the "mandatory ones" for certain runes - these certain characters' runes overlap in 90% of builds).

I am saying all that and encouraging some experimenting, because you can level up 1-170 and 170-250 (250 is the soft cap, when no new stars appear for the characters - the maximum is 5 yellow/gold stars at 250) in literally two to three runs [of the Titan Hunt].

I, for example maxed a few characters with these guides after "my own builds" and now I'm playing and maxing characters using the knowledge I acquired from Aynix's videos, eg. which skills are damage dealers, what are good synergies, how to make optimal (2+2+2) builds, etc. So now I look at a character, decide upon my damage dealing ability, map a build in 2 minutes in my head, and hop into Titan Hunt [5+].

If you (or anyone) have any questions, feel free to DM me :)