Get better equipment, equip stronger mods. Basically your combat rating is an average of all the item levels of your gear. Down near where it says the durability and such of your item should be an item level. If you have a mod equiped it should be one number plus another, that is the increased level from the mod.
An important note is that you do not even have to be able to equip an item, it just has to be in your inventory, or your bank, to increase your CR. This means even if your a tank and are carring around a controller weapon your CR could go up if it's higher than your current one. This is however a false CR and most likely mean while you could get into a raid, you would still suck and contribute next to nothing to the group other than trouble.
"That is not just scraping the bottom of the barrel, that is lifting the barel up and poking some of the slimy sludge growing underneath the barrel."
Is very easy get 43 cr minimum with a new fresh lvl 30 and 43 to 53 can be done in 1 or 2 days with some luck (i did last week). Required have another main character to buy the items or farm them in T2:
Vest of magician lvl 58 (abra chest) - Star helmet lvl 52 (oan drop) - grona back lvl 52 (oan drop) - grona glove lvl 52 (oan drop) - any purple Stars weapon lvl 52 (drop in most of the FFTL) - 2 ring blues lvl 40 (most are in chest from T2 or drops from trash enemies T2) - neck any of lvl 34 you can find in drops should be enough - legs any from chest drops in T2 are lvl 40 - feet you can use supergirl is lvl 38 i guess - waist you can use bane belt is lvl 38 iirc. With all this items you can easy get 43 atleast if no more, you can also mod all with beta plan to raise 1 or 2 lvl and don't use many exobytes. Is important you don't have to equip any of this items , because cr increase by holding them not wearing, in case you wanna use them later for other toon.
If you manage to get 43 to jump to 53 is even easier, first do the T2 duo, there drop legs, head and chest blues lvl 56 (you already have your vest of magician lvl 58 so not replace that) then go to do LOA you may find LOA mask item lvl 51 in first try and win roll, then do Star Lab you may find waist and legs from lvl 48 there for your role, next oan any possible replacement for any of your equipment lvl below 46, after you do those 3 alerts you may have close to 50 cr or maybe a bit more, run the Outer raid, is the easiest one with drops lvl 48 you may replace your neck lvl 34 and any other low lvl equipment.
I get 53 cr replacing the neck lvl 34 i was using, also if you have a league ask them to walk in FOS3 all weapons are lvl 62 you can increase even faster the cr.
After you reach cr 53, CC daily is the best you can do since are 18 MOM per day and very easy to obtain 1 hour if you do it fast all marks, also CC items are the second best items in the game now, weapons are the best so far in pve.
MoCs are earned via PVP matches. Either arena or legends. Do note that the gear has a lower cr and isn't generally advisable to wear in PVE situations. There's a level 30 set that can be bought for cash(game not real money) to get you started if you wish. Can't remember where the vendor is in the maze of the Watchtower but villain-side, it's in the far back section of the meta wing.