Hi
Highlights:

you pressured a safe group at the bottom and lost sente

bad shape allowed Black to strengthen himself in sente

pressuring the lower side once more lost sente again, while you should have cut/attacked the groups at the upper right

another threat against Black's super strong group was ignored and Black settled things actively on the right side
From these highlights it is easy to derive a theme: "are my moves really sente"?
Black had a sharp, greedy attitude in this game. It was a good game so I wouldn't be too disappointed.
(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[6.50]
PW[dumbrope]PB[Black]WR[6k]BR[6k]RE[B+Resign]MULTIGOGM[1]
;B[dp]
;W[pp]
;B[dd]
;W[pd]
;B[nq]
;W[qn]
;B[pr]
;W[fq]C[Knotwilg: although the opening is free at our level, your choice here can make the game complex for White]
;B[fp]LB[cn:B][hq:A]C[Have to think about this as I expected black to either pincer H3 or answer C6]
;W[gp]C[Could have played E4 because the ladder is okay.]
;B[eq]
;W[fo]
;B[ep]
(;W[go]C[I chose the simple, thick way, but..]
;B[gq]
;W[hq]
;B[fr]
;W[dn]LB[gr:A]C[Accordifng to joseki books, white should atari G2 first. I know this, but for some reason I can't convince myself that is good.
Knotwilg: in this game, the bottom is not important so indeed it doesn't seem called for]
;B[hr]LB[qq:A]C[Of course this is why the atari G2 is joseki..MUST FEEL THE PAIN AND BELIEVE...
Knotwilg: not at all. White plays the unimportant side]
(;W[iq]LB[mc:B][qq:A]C[Knotwilg: I would either tempt Black into playing at the bottom once more (A) or tenuki immediately (B) See variations]
;B[qq]C[Knotwilg:
Your move was not sente and Black gets the corner which is a bit painful]
;W[qk]
;B[nc]C[Knotwilg: Now Black has the initiative to develop]
;W[cf]
;B[ch]
;W[ef]
;B[ck]
;W[fd]C[This feels good.
Knotwilg: agree]
;B[fc]
;W[gc]
;B[ec]
;W[gd]
;B[ce]LB[bd:A]C[Seems to help white. I found a few pro games where black plays B16, which seems better to me, too.]
;W[df]C[I look at a lot of things here.]
;B[be]
;W[bf]
;B[kc]C[Knotwilg: although Black's play looks extremely greedy, it's not easy to punish him.]
(;W[cm]C[Knotwilg: I agree with you here. After looking at the variation, it seems that Black gets too easy a game if you answer in the upper right.]
;B[qf]C[Knotwilg: this must be too aggressive]
;W[pf]LB[nc:A]C[Knotwilg: it seems more natural to lean on the strong stone A]
;B[pg]
;W[of]
;B[qe]
(;W[od]LB[oc:C][nd:B][qd:A]C[This is a heavy, non-move. R16, O16 and O17 are all joseki. My reasons for rejecting them in favor of this are likely flawed.]
;B[rc]
;W[ek]C[Not knowing how to continue in the upper left, I came back here.
Knotwilg: a very good mentality]
;B[dl]C[I think I miss some basic shape moves here.]
;W[fm]C[Knotwilg: good technique]
;B[dm]
(;W[en]C[Knotwilg: there's better shape. See var]
;B[cn]
;W[co]
;B[bn]
;W[bo]
;B[bm]
;W[do]C[White damages black's corner but gets settled a bit too easily. I am not satisfied.
Knotwilg
If you look around the board, indeed Black has had it too easily. His stones are settled or have enough room to flee. White is not super thick, rather heavy in some places. ]
;B[og]
;W[mf]
;B[ng]
;W[ld]
;B[lc]
;W[md]
;B[mc]C[Estimating the score, black is ahead. It's hard to know what to do with the thickness as I can't find black weaknesses. There is some funniness at the top, though.
Knotwilg: see var]
(;W[mp]C[I considered K15, but wasn't sure it was sente.]
;B[mq]
;W[lp]C[But continuing here is certainly gote, so...]
;B[je]C[Black takes this point.]
;W[kf]
;B[lh]
;W[jf]
;B[ie]
;W[ni]C[At this point I just feel white is losing. If this is forcing, I may be able to build some moyo.]
;B[oj]
;W[mi]
;B[oi]
;W[mg]
;B[mh]
;W[nh]
;B[lk]C[Knotwilg: Black is overdoing it]
(;W[mk]C[My 1st instinct was M11.]
;B[nk]C[I saw this but didn't think it worked so much for black.]
;W[ml]
;B[mj]
;W[li]
;B[lj]
;W[ki]C[Knotwilg this is great because you become thick with points]
;B[nj]
(;W[qi]C[Knotwilg: I thought the cut would be better but it doesn't work]
;B[pi]
;W[qh]
;B[qg]
(;W[cq]C[Knotwilg: this is not the time to leave the front. This must be Black's strongest group.
I would call this the losing move (if the game were really lost at the end)
See variation]
;B[qm]C[I did not find the correct answer to this, if there is one. White does have some thinness, so maybe an earlier mistake.]
(;W[ql]
;B[rm]
;W[pm]
;B[rn]
;W[qo]
;B[ro]
;W[ol]
;B[nl]LB[pb:B][ic:A][dj:F][nm:C][dr:D][ir:E]C[White has no game. I resigned.
Knotwilg: I understand the disappointment but there are a few ideas you can still pursue with all that influence around the board.])
(;W[pm]
;B[ql]
;W[pl]
;B[rn]
;W[qo]
;B[ro]
;W[rk]
;B[rm]
;W[pk]))
(;W[ic]
;B[pb]
;W[qb]
;B[pc]
;W[qd]
;B[qc]
;W[rd]))
(;W[oh]
;B[pi]
;W[ph]
;B[qh]
;W[qi]
;B[qj]
;W[ri]
;B[rj]))
(;W[li]))
(;W[pb]
;B[ic]
;W[qh]
;B[qg]
;W[rh]C[White can expect something from attacking Black's strings ]))
(;W[do]LB[fl:A]C[Knotwilg: this good shape connects all stones. The left side is a ladder.
(there is some aji at A though)]
;B[cn]
;W[bn]
;B[co]
;W[cp]
;B[bo]
;W[bp]))
(;W[qd]
;B[pe]
;W[oe]
;B[od]C[If white doesn't find the right move here, it's dangerous...])
(;W[oc]
;B[nd]
;W[pe]C[I did not like black's option to force here. In particular, because I imagined answering at P16 rather than here, which would have been worse. Now that I see this, it is not so bad for white.])
(;W[nd]C[I simply forgot about/didn't consider this move.]))
(;W[pf]
;B[pb]
;W[qc]
;B[bm]
;W[co]))
(;W[qq]
(;B[kq]C[Suppose this exchange]
;W[ci]C[For me, White's development is at the larger scale and therefore better])
(;B[nc]LB[mp:B][lq:A]C[Black can tenuki but his flow is not as natural as in the game and White can attack the bottom anytime in any way.]))
(;W[mc]
;B[qq]C[If Black comes here now]
;W[qk]LB[mc:B][iq:A]C[White is building.
In the game, White has a stone at A instead of B. If you could choose now, I'm sure you'd pick B.]))
(;W[fr]C[Honestly I don't know this one well.
Knotwilg: also this is the wrong direction. These stones need White support to the right.]
;B[ip]C[And don't feel comfortable if black plays here.]))