Cream of the Crap

Unlike other survivors Rita is rather limited when it comes to other than survivor cards. Her stats are rather good though, compared to other investigators, especially when you have Dark Horse in play as soon as possible. Unfortunately, Dark Horse only works if you have zero resources, so expensive cards are a bit of a problem for Rita, because you'll have to decide every upkeep phase whether or not to gain a resource.

However, Fire Axe is a very useful weapon, as it lets you spend resources in order to improve your strength when attacking (up to three resources per attack, which gives you a phenomenal boost of +6 strength). Combined with Rita's base strength of three Fire Axe makes her a formidable fighter. Additionally, if you spend the last of your resources this way, Fire Axe also gives you +1 damage. Thus, Rita will be able to deal with most weaker enemies, especially since many enemies have 3 (or another odd number of) health and you'd otherwise have to spend two valuable charges from spells or weapons to kill these foes.

A great combo to combine Fire Axe with is Drawing Thin. This lets you increase the difficulty of a test by 2 in order to gain... 2 resources! Say, you spend one resource (or two, if you have Drawing Thin twice in your play area) to boost your strength, you'll get back double the amount of resources that you spent for the strength and damage bonus of Fire Axe.

Since Rita has a base Agility of 5, it is very easy to use Track shoes, Peter Sylvestre, Trench Coat or Dark Horse to boost your Agility to 8, which also lets you easily take advantage of Drawing Thin when e.g. evading in order to gain resources for more expensive cards like Pilfer, Waylay or Will to Survive.

You could have a copy of Emergency Cache in your deck, just in case you need Resources for an expensive card, but Madame Lablanche will also give you one Resource per turn if you don't have any.

Because of Rita's high Agility, Waylay is very useful to dispose of exhausted non-elite enemies. Will to Survive becomes even more useful when you can buy XP cards that increase the number of actions you have per turn.

Since Rita's Intellect of 2 is rather meagre, there is no point trying to boost it by way of assets or allies. So you'll depend on cards like Look what I Found or Pilfer, which lets you find up to three clues at once.

Live And Learn is just as useful as Lucky! - plus it's free!

Use Resourceful to regain other Survivor cards like Lucky! or Waylay from your discard pile if necessary. Scrounge for Supplies in turn lets you regain Resourceful, so using these cards in combination will let you have repeated access to powerful cards.

I think Last Chance, which gives you 5 wildcard icons when you commit it to a test (minus 1 per card in your hand) is even more useful than Unexpected Courage.

Rita's low sanity of 5 makes Cherished Keepsake obligatory in your deck. Best allies are Peter Sylvestre and Madame Lablanche, especially after you buy Charisma so you will have an additional ally slot. Peter Sylvestre is great to shield Rita from taking horror, as he can heal one horror per round.

All in all, especially because of Dark Horse you'll likely want to rely on a deck of rather inexpensive cards and you'll have to carefully plan ahead what you want to do next turn, i.e. whether to get one Resource during upkeep phase or not. Rita's signature card is rather weak compared to other investigators' (as is her Eldritch Sign bonus). However, you may often take advantage of her special ability of dealing damage to enemies or taking an extra move action when evading.

You should be able to team up Rita with any other class or investigator, but be careful about pairing two investigators with low Intellect as otherwise you may have a hard time when trying to Investigate.