Hmmmm..... Well.. I can tell you a story. My MC username is pichu115, because, well, uh der der DEERR I was little and I love pokemon. So that's my gaming username I've decided. Then I realized, "All the good names don't have numbers for no good reason! Must, think... of a better username!" And soo I went to youtube, looked at peoples usernames, and then said, "People use numbers as if they were letters! I'll just do that with my name! 115, you're now an i-i-s!!!" And that's how it happened :l So I have a suggestion for you. You said you like no numbers, and wanted the first letter capitalized. Here's my idea:
DerpTheEaten
NinjaingDerp
WafferLord
Eat_da_Pie
Vilerininj [Vei-LAR-i-nieenjh] <--- pronunciation
(Idk thinking while doing this and skype calling is hard!! >.<)
(I like your dogs name) Wolvergon
Hiferider [Hief-eur-RAI-dier]
Here's some advice if you don't like any of the suggestions too- you can use either you nickname or your first name as an incorperation to your username, you know,
Like Tobuscus, inthelittlewood, SoTotallyToby, SkythekidRS, Zoeya, SashiMimi. (btw those names are taken!)
Really simple, right? Well you can also do things you're known for, like let's say you're short, the name can be something like IAMShortii (Taken!)
Let's say you want just a simple word to be your name. Well in that case you can tweek it to where the username will be know by you and you can use it as a username, Like ihasCupquake, or PewDiePie (Both taken!) You get what I'm saying. If you still can't think of anything then sorry D: