If you’re a person who takes your solo queue climb seriously, the correct response to getting autofilled into a position you aren’t comfortable with is to dodge and requeue. However, for those of us who don’t like to waste time and don’t mind having a lower chance of winning some games, it’s important to have a plan for a secondary role.
First you need to choose a secondary role that you want to go to. If you queue as fill in your secondary, it will only make your life more complicated because not only will you be having to play champions you aren’t comfortable with, but you’ll have to play in roles you aren’t comfortable with and be unfamiliar with the matchups. Not knowing which position you’ll be playing will require you to adapt much quicker to each game and the shifting meta within each role. This is possible, but certainly not recommended if you want to climb the ranked ladder and improve at the game. There’s little to gain from playing one specific matchup in an off role and then never doing so again. It’s important to build your game knowledge slowly and diverting your knowledge too thinly over multiple roles and matchups is very inefficient in terms of improvement.
This is not to say there is no benefit from playing other positions. In fact, I strongly recommend playing a few games of every role and if you can, you should play every champion at least once to get a feel for their abilities, strengths, and weaknesses. However, this should be done in normal games where you can practice and identify key concepts of each role. For ranked, you should still be focused on one role and a small pool of champions to pick from.
Great picks for your New Role
Your secondary role should be chosen based on what champions and playstyles you are already comfortable with. To make the transition easier, I would recommend only playing one or two champions when learning your new role. Ideally, it would be a champion you already have experience with, but this is not always practical. For example, if you are an ADC main and you like playing Lucian, it will be much easier to simply play Lucian top or mid than to learn a completely new top or mid laner. This is the advantage of learning flex picks who are proficient in multiple roles. Flex picks are often highly contested in competitive League of Legends due to their value in the drafting phase, so they tend to be nerfed more frequently than other champions. Because of this, it’s a good idea to do some research on which champions you play are also being played in other roles, as this changes quickly over time depending on the state of the metagame.
If no strong flex picks come to mind, the best role will be one in which you can play a champion you enjoy playing. If you’re not sure where to start, simply do some research into who are the strongest champions in each role. It’s also good to look for a low complexity champion, since you’ll be primarily learning macro information about the role, so you don’t want to pile on the learning difficulty by playing a complicated mechanically intensive new champion. Some strong, relatively easy champions to try for each role as of patch 10.19 are:
Top: Darius, Garen, Maokai
Jungle: Nunu, Warwick, Hecarim
Mid: Annie, Diana
Bot: Ashe, Miss Fortune
Support: Lulu, Leona
These are just suggestions of course, but I would recommend getting comfortable with one champion you can play in an off role. This way, if you get autofilled into your secondary role, you have a champion you can rely on. For top and jungle especially, it is generally easier to play tankier, safe champions since they won’t get punished as hard for making small mistakes.
Pick a secondary role based on your main role
Another thing to consider is what role you currently main. If you main Top, Mid will be an easy transition since it's still a 1v1 lane scenario where you have complete agency over the matchup and your lane. Things like wave management, matchup knowledge, and being aware of ganks are all things that will be useful in both roles. There are many top laners who are viable mid laners such as Renekton, Mordekaiser, Sett, Akali, Vladimir, and Jayce.
If you main jungle, Top or Support will fill a similar role. Top is similar in that the style of champions can be vary similar, as there are many bruisers and tanks who play in the Top lane and in the Jungle. However, if the thing you love about jungle is enabling your lanes and looking for ganks, you can play a Support who roams a lot and get the same satisfaction in helping your team. One issue with picking a secondary for Jungle is that many junglers don't function well outside of their role. Although you may need to learn some new champions if you play support, the Top lane tends to have more viable champions who Jungle such as Volibear, Olaf, and Trundle.
For Mid laners, I would choose either Bot or Support. Bot lane because you will be able to use your mechanical skill you've learned in the mid lane to escape pressure and maximize damage as a Bot laner. Support will be an easy transition especially if you're willing to play mage supports, since this will be very similar to playing mid lane in terms of laning. Depending on the matchup, you can take Mid laners like Orianna, Syndra, and Karthus into the Bot lane, where it's like Mid but you have a support to help you. Mid laners such as Xerath, Vel'koz, and Lux easily fit into the Support role as well, making this switch very easy as your champion pool doesn't need to increase.
For Bot laners, Mid or Support are probably your best bet. Transitioning to Bot lane will be simple because you'll already have experience with the 2v2 matchups, and what supports complement which Bot laners and counter other Supports. If you need to do damage however, the Mid lane might be a better option since you can still benefit a lot form farming efficiently, avoiding enemies focusing you, and outputting the most damage possible on key targets. There aren't many Bot laners who can Support outside of Senna, but Bot laners like Lucian, Tristana, and Kalista can easily transition into the Mid lane depending on the matchup.
Finally, for Supports, Mid or Bot will be the easiest transitions. Although you'll have to get used to farming and positioning better, the Bot lane will be an easier transition since you'll be playing in the same lane, so you should have an idea of what to do and what different matchups looks like. The Mid lane could be a good fit as well since you're probably used to playing some mages like Zyra, Lux, and Morgana. These champions can sometimes work in the Mid lane, but even if they don't, learning other mages won't feel too difficult.
All roles have their challenges, but there is a degree of variance in terms of how forgiving each role can be to new players. If you’re not a jungler, I generally wouldn’t recommend choosing jungle as your secondary role. Jungling well is very different to laning, and the knowledge you’ve gained about the lane phase won’t help you much when you’re trying to clear camps efficiently and track the enemy jungler’s pathing. Mid lane and bot lane champions tend to require more mechanical skill, and although these are fun roles, be prepared to learn some mechanical skills to succeed, especially in the bot lane where getting every last hit while simultaneously being targeted by the enemy team can be challenging at first. Support is the most forgiving role to be new at. If you really don’t know what to pick (and you aren’t a support main), I would recommend picking support as your secondary role. Even if you don’t ward perfectly or lane perfectly, if you use your abilities when fighting and do your best to protect your bot laner, you’re doing most of what is expected of you. Enchanters are great because you just need to stay out of the way and use your abilities in fights. Simple engage champions like Leona are straightforward, you just need to decide when it’s the right time to use your all-in combo, and on whom.
No matter what role or champions you choose to play when you get your secondary role, it’s important to practice some games so you aren’t going into a ranked game with no knowledge of the champion you're playing, the matchup you’re in, or what your role is supposed to do. If you take some time to learn another role and champion, you’ll expand your game knowledge and gain confidence in more diverse situations in game.