Lol I moved once. My tank started at the edge of a base and then I backed it around a corner behind a wall so that I could fire my LRMs indirectly over the wall (spotted by battle armor) while I waited for the mechs to turn the corner so I could smack them with lasers and SRMs. The only other time I would have thought about moving is if I had a straight shot at exactly 5 hexes away from a mech then I may have considered a charge at max speed (max speed of 5) since as being an 85 ton tank I think I may have had a fair chance at taking a leg with a charge if I got lucky (though I am not sure as nobody wanted to look up the charging rules with tanks so I could find out the damage at the time).
you used your 85 tonner correctly then. scenarios where you can rely on the enemy 'coming to you' is where those assault class vehicles shine, they don't do well in pursuit, breakthrough, or any sort of maneuver combat, but they're great as what they are (and teh rules encourage them to be), which is bunkers.
If you're an "offense" player (but don't like to rely on hoverengined hovercraft or the WiGE hovertank playng style), 4/6 is the slowest base movement you can use for playing offense, and at 4/6 you want to be fairly heavy. (Manticore, Patton or Po unless you can afford that omnitank thing they gave the Fedsuns). in the 55-40 ton bracket, you want a minimum 5/8 if you intend to play offense with your tanks (Myrmidon is your poster-child here). Below that, invest in Hovers or VTOLs (But NOT the craptastic Yellowjacket. sure it's got a big gun, it also has a big rotor and losing movement means falling out of the sky to the death of your crew, or redistributing Poland Model A gauss rifles as lucky salvage to the enemy,instead of gauss rifle slugs at high velocity.)
Playing offense with tanks is something where you begin your planning by expecting to lose units. Even in today's much, much, longer rolling fest for tank damage, you're not QUITE as tough as a 'mech when it comes to playing offense-it's going to be easier for the enemy to counter them, take this into account, and compensate for it in your tactics.
for example: move into "Hull down" positions whenever possible before firing, but don't linger there more than 1-2 rounds, keep as many hexes as you can manage at cruise between you and your start-point every movement phase, make use of your turret, to keep slinging shell until you either lose turret motion, or run out of ammo, space vehicles for mutual supporting fire, but not so close that one artillery strike from an Arrow IV can nail both.
GROUP your SHOTS. if you have 3 potential targets, pick the one that you have more units in a position to hit them with, and concentrate that fire with all available units. Tanks on offense are all about bringing it to decisive QUICKLY, before you lose too many MP or have too many units locked up/knocked out. losing 1/4 of a 'mech lance is more of a problem than losing 1/4 of a tank company.
Run similar chassis. If you do nothing else, all your tanks of a given weight should be the same model and class. This simplifies book-keeping and it simplifies mass fire by grouping them together for movement and engagement. Running in pairs with just a couple hexes of separation also means that when his light 'mech jumps onto one of your tanks, the other can 'scratch the back' at good to-hit numbers. It also means that there is no way in double-blind that you're not going to see that enemy unit.
this stuff is basic, you probably already know all of it. the takeaway is the first statement: assume you will lose units and plan accordingly. Move your tanks in a staggered echelon, roughly 2 hexes apart across open terrain, where each wing pair is within short/medium range of each other, with fire envelopes from main guns overlapping. In urban, stagger them in column formation with VTOL support a similar distance. This relieves SOME of the pressure the other side can apply using physical attacks. Not all, just some.
with small LRM racks (5s) use smoke rounds to screen your forces wehn crossing open terrain against heaiver or clantech forces. a company of Pattons laying smoke and loading Precision in 3055-3060 play can wreak havoc on a star or even a Nova of clan units by using PA instead of standard shot out of those outdated 3025 era main guns. a company of Po are even better at this due to the effectiveness vs. Suited infantry. for lighter use, Myrmidons should carry infernoes whenever possible, to make life less comfortable for points of Elemental BA or similar forces. Infantry on the attack should probably best be handled with Mechanized as opposed to Motorized, and should ideally fill in the gaps between tanks in the formation, riding somewhere in the gaps between your leading and trailing echelons, to give them reaction room once the enemy is engaged, except in forested or urban terrain, where your infantry should ideally be running point/flank security.
when working with BA, it's by faction and type. quad suits like the Fenrir fill in the gaps between tanks in formation, or run ahead where it's convenient (sweeping through buildings or wooded areas to get ahead of the formation.) Humanoid suits should likely be devoted either to Battelemech support, or partner with your self-moving bunkers in a defensive arrangement, as they can't keep up with your faster tanks. Fa Shih, of course, can 'tank ride'.
when working in conjunction with 'mechs, the 'mechs should ideally be kitted for close range or sniper duty, and match or exceed your tank units in movement. They're tougher, let them take point whenever it's practical and use your tanks to exploit what they open up, again, concentrate fire whenever you can to keep your 'mechwarriors in fighting trim by reducing the amount of damage they have to soak via killing the enemy faster. for faster, tougher designs meant to close-up and scrap, (Wraith, some variations of other 55 to 65 ton 'mechs over 5/8) a diamond formation works best-the trailing tank should be in medium range for your point 'man' in the 'mech, with the 'wing' tanks being at short to medium with either main guns, or long-ranged secondary weapons. (Gauss Rommel is a good choice for wing/trail tanks, but Po with that lovely LBX is also a good option. avoid Ultra-Patton like the curse and plague it is-the Ultra always jams at the worst possible time, and requires going back to the rear to unjam it.)
Tanks to avoid on offense: anything that lacks a turret. if you can't get 360 degrees sweep with your main gun, you're going to be exposing yourself to accurate return fire just to get one or two shots off before being immobilized and taken (effectively) out of the fight.
Tanks to avoid on Defense: same thing, unless you've got a map-decided choke point and hidden units rules in play.
The exception: SAvannahmaster, hovertanks with good speed (7 or more) on swampy, flattish ground.
Movement on Offense should resemble a school of fish-that is, your tanks should move as one, changing direction as one, choosing a vector as one. Tanks work best in open-spaced phalanxes. If you want more 'spread out' bring other unit types (VTOL, hover, 'mech) if you lose tanks in the center, drift one flank or the other (or both) to close it up, but always, always keep moving.
