Would you help me to make the table below look better? I don't need a beautiful table, just some frequent practices to make it looks better.

**MWE**

```
\begin{table}[H]
\centering
\begin{adjustbox}{width=0.8\textwidth}
\begin{threeparttable}
\caption{Estimación de pKa para ácidos, alcoholes y aminoácidos}\label{table:estimación_pka_RM1_con_aminoácidos}
\begin{tabular}{|l|c|c|c|c|c|}
\hline
 & \textbf{} & \multicolumn{4}{c|}{\textbf{RM1}} \\ \hline
 &  & \multicolumn{2}{c|}{\textbf{COSMO}} & \multicolumn{2}{c|}{\textbf{SS-COSMO}} \\ \hline
 & p$Ka_{\textrm{exp}}$(298K) & p$Ka_{\textrm{calc}}$ & $\Delta$p$Ka$ & p$Ka_{\textrm{calc}}$ & $\Delta$p$Ka$ \\ \hline
\textbf{Ácidos}&  &  &  &  &  \\ \hline
acético & 4.75 & 2.1 & 2.6 & 4.2 & 0.6 \\ \hline
láctico & 3.86 & 0.7 & 3.2 & 5.0 & -1.2 \\ \hline
benzoico & 4.2 & 1.1 & 3.1 & 1.6 & 2.6 \\ \hline
\textbf{MAE} &  &  & 3.1 &  & 1.6 \\ \hline
\end{tabular}
\begin{tablenotes}
\item[a]{Desprotonación de referencia}
\item[b] {\scriptsize Sin valor experimental}
\item {\scriptsize Estimación.}
\end{tablenotes}
\end{threeparttable}
\end{adjustbox}
\end{table}

```