Inf main here, my fastest time getting to the enemy gen is <25 seconds, it takes 2 and a bit stickies to take it down. From there I take out the other base assets with a single sticky or however many explosive shots it takes. Check the scoreboard at the beginning of the match, if you see that the enemy has multiple techs you may want to use 3 stickies to take the gen down faster.
I don't know what weapons you are using, but SSF and SMG are more reliable for me than the Jackal and you don't feel like an ass. Plus using the fusor will improve your aim with fusors on other classes.
Perk wise I find survivalist to be a must have for the huge amount of energy you get on pickups. The other perk can really be anything, I run close combat since I also use the shocklance but looter and safety third are good for stickies and mines respectively.
I wouldn't use smoke nades since they are basically a get out of jail free card and when not using them you will find yourself throwing a sticky trying to cloak. If you do use them take note that you will NOT cloak if you have no energy. Take note that mines will deal full damage no matter what range an enemy triggers them.
I personally find shocklance to be the best secondary but knives and the pistol are also great.
Just some general tips here:
Using your secondary, shoot a tech turret once and then melee it for an instant kill (this also works on medium classes but it takes a few pistol/knife shots).
On snowy maps like katabatic you will produce 'puffs' while walking on snowy ground. Enabling ski will stop this. If you go into 3rd person mode you can see this for yourself.
I find it a good idea to enable skis indoors as your footsteps will make an audible sound that other players can locate you with. I have jump bound to right click and I bunny hop whenever I need to change direction while slow skiing.
Something I see other infs do a lot is cloak when there are no enemies around, you can walk around and let your energy recharge since you instantly cloak. Changing direction is also a good idea if someone sees you as they will try to predict where you are going.