In soloqueue, it's hard to say what your comp will end up looking like. In general, pick your champion to synergize with the champ you'll be interacting with the most. Full team comps are hard to get unless it's a premade.
Thus:
Top Lane: Pick a (usually tanky/bruisery) champion who synergizes well with your jungler.
/
is a good example of this kind of pick, and a setup which has been utterly oppressive in LCS this year. Gnar packs either immense CC or powerful ranged damage, both of which work well with Jarvan's engage-oriented kit.
Jungle: This is one of the trickiest picks, since you'll have to work with every single lane. Typically, I try to pick someone who counterpoints the midlaner's pick. For example, if it's a CC-heavy mage like
, I might go for an engage-type assassin like
. However, if my mid picks
, I'd choose a more CC/support-oriented jungler like
or
to fill in that gap. Again, jungle is one of the trickiest picks to make. Try to base your choice off of your team's strengths and weaknesses.
Mid Lane: As the midlaner, you have a bit more freedom of choice, since many common mid picks are multifunctional, such as
(either a slippery uncatchable mage or a lethal pick-off champ),
(massive burst capability and two AoE CC tools), or
(ranged harass combined with immense all-in potential). As such, your choice can be based off of your preferred playstyle. Remember to consider the rest of your team when making your choice, though. If your team lacks CC, don't pick
, pick
.
ADC/Support: Playing in the bot lane is a bit like playing your own little minigame in League. You should see some jungle presence from both sides, but don't be surprised if you don't see your jungler more than twice, and midlane roams will be rare. As such, your pick should be focused on synergizing with your lane partner. Good examples of this include
/
,
/
,
/
, and
/
. Your two picks may not synergize with the rest of your team as well as they could, but since a good lane combo will generally get really strong anyways, it shouldn't matter. Again, do try to pick into your team's voids. No assassin? Don't pick
, pick
. Have tons of single-target damage, but lacking in AoE sledgehammer?
will outperform
. Need CC? Get
instead of
.
TL;DR
In the top lane, pick a tank who works well with your jungler.
In the jungle, pick someone who covers your mid's weaknesses.
In mid, pick someone who fills in your top's missing pieces.
Support/ADC should primarily focus on intralane synergy, but don't forget the rest of your team.
Still TL?
Pick to cover your team's weaknesses. Get CC if there is none, burst if it's needed, tankiness if your team is full of squishies. Just don't leave any gaping weaknesses to be exploited.