Depends on what you use the most cert the class that you like using, if you mean my lightning setup get at least the first level each slot at minimum, at present my anti infantry loadout (dont go anti vehicle until you get AP) is
c75 viper with thermals (just starting off go for the 1.5 zoom optics) get a few ticks into the ammo capacity, and when you can afford it get the first slot at least of reload speed, it will drastically increase your dps. The Viper cannon can do a semi decent amount of damage to enemy vehicles but it doesnt have enough damage to win outright against anything other than a harraser, another viper/skyguard lightning or a non shielded sundie, dont be afraid to shoot at enemy aircraft either, with teh 6 shots you can spam in their general direction and might get a few shots to hit (note: don't do this when not in a medium or smaller fight 90% of the time they will just target you and destroy your lightning)
Rival chassis as being able to face front armor towards threats is key to surviving in a tank, and being able to do some sweet drifts is awesome. Also be very aware of enemy rotation as their angle towards you will dictate how much damage you do to them, its about double the damage if its a rear shot.
Nanite auto repair as you can repair while fleeing but it doesnt really do much until you get a few more levels into it, also get as many certs into the repair tool for the engy as possible. I am not a fan of any of the armor options as being at max health when you start every engagement is very helpful in surving in your tank.
Either fire suppression or smoke launchers, personal preference.
Dont expect to be able to take on any other tanks, focus on infantry fights and splash doorways and corners. The viper cannon has 6 shots and has a bit of recoil the recoil is reduced if you are firing directly forwards. Get into the habit of stopping before firing at all times where possible. It will kill with 2 direct hits and i believe it can kill maxes with about 2-3 sets of 6 shots depending on if you direct hit or splash nearby. I believe that its a ohk on infantry if you hit in the head.
Also get tank mines for your engy, focus on planning your escape route or cover position and place tank mines along that path to lure enemy vehicles as they will think you are an easy kill and if you can keep them concentrating on you and not the path in front.
For the implant i pretty much always run enhanced targeting as it enables you to prioritize targets depending on their health and you may be able to snag a few free kills on other vehicles that are at reduced health.