Just remember modern is a T4 format. This means MOST decks are built to win or can win on turn 4, or survive turn 4. Tron and turn 3 karn, twin and turn 4 infinite 1/1's, high tide infinite mill etc... Storm turn 3, 40 damage grapeshots etc..

I'd definitely take from tier 1 and 2 decklists and work from there if you want to customize it. Modern is a format people enjoy because you buy your one or two decks and thats it, no more investment like standard.

Many people at my FNM's are playing the same exact affinity/infect, U/R twin, R/G tron etc...decks that they built a few years ago. One investment on a deck and you're good to go!

Affinity is a SUPER fast paced deck, many times you'll have turn 1, laying 3-4 cards, I think though for you you'd really like U/R splinter twin. It's 'basically" a control deck that's win condition is infinite creatures.

The thing about Splinter twin, is that the deck isn't built to control and last, it's built SPECIFICALLY to win on turn 3 with infinite creature combo. It's a tier 1 deck and has been for quite some time. If it doesn't get the combo on turn 3, it runs tons of counterspells/remand etc until it gets the combo, usually that's within only a few more turns.

Twin is ALWAYS a threat, and incase you don't have combo on turn 3, you just control it for a few more turns to get it.

Other decks are burn, or infect decks but they are straightforward (as most modern decks are) and don't have much options for answering opponents threats, they simply win from being the greater threat.

Remember modern decks are built specifically for a purpose and the deck DOES that gameplan very well. Many of the counter things are going to be in your sideboard after game 2.