Best way to get to level 10?

sell unused trading cards, buy the cheapest ones to make badges

edit: or play lots of TF2 or CS:GO is you got that; get weapons and stuff, sell it, buy cheap trading cards, make badges

Do the same as you did to come to level 9,maybe

Wait for summer sale trading cards I guess

TremorGames sells full sets of cards for fairly cheap. I bought the Arkham Asylum badge this morning after like 2 offers.

money free: trade for cards
I bought CS:GO when it was on sale, I already got back the game's price from the drops, and some extra moni as well.
There is no "secret" way to get steam XP. Altho you can get hired by Valve, to get a Valve employee badge, or get your game greenlit (100$ posting fee) and you get a steamworks developer badge

well, you can complete "Pillar of community" - this will give you 100 exp; and win few extra games - each game gives you approx. 3-5 exp.

Play Dota 2, i got about 25 euros from last event which lasted for like a week.
U get item drops, sell on market, and craft badges. (and buy games)

Alternatively idle in CS:GO / TF2 for items.

you can easily get another 100 xp completing another task in the community badge, like a message in the steam discussions as i see in your account...

can't help for the other 10 xp

Srin

Become a Valve employee (+1000XP). Easier ways are adding games to your account or crafting badges. I use this to find cheapest sets of cards.

And like others said, complete Community Ambassador badge.

Go to Tremor Games and see if you can earn enough Tremor Coins to spend on some games that drop trading cards (or even spend the coins directly on cards as they have them there). Trade these cards until you have a full set and craft the badge.

Easy tip but you do have to spend money.. Buy any bundle with crap games, idle in each of the games for the free cards, sell the cards for games that gave you dupes and finish the set for any one game.

Finish something from this - I guess doing "Post in the Steam Discussions" would be easiest - and you'll get 100xp.

After that - get cards from at least two games and either sell one game to buy missing cards in 2nd, or use some trading bot to exchange them.
Or buy some bundle with Steam games - each game gives at least 1xp.

Or if you're patient - wait until 4th November. Each year on Steam is another 50xp for you.

Thank you all i'm level 10.